AMERICAN SOCIETY OF CIVIL ENGINEERS
Founded November 5. 1 8 5 2
TRANSACTIONS
Paper No. 2222
__
CHARACTERISTICS OF HEAVY RAINFALL IN
NEW MEXICO AND ARIZONA
BY LUNA B. LEOPOLD,~
JUN.AM. SOC. C. E.
WITH DISCUSSION
n y MESSI~S.
LAWRENCE
PRATT,
L. L. HARROLD
AND A. J.
DICKSON,
JAMESG I I ~ A N DCLARENCE
,
9. JARVIS,PAULV. HODGES,
EDGAR
E. FOSTER,
R. W D A V E N P ~ H
A.TI<.
, SIIOWALTER,
WALTER
B. LANGBEIN
EMILP. SCHULEEN,
AND LUNAB. LEOPOLD.
SYNOPSIS
Seasonal differences in storm types are typical of New Mexico and Arizona.
Summer storms ordinarily are of small areal extent and are characterized by
high-intensity. rainfall in a well-defined pattern with relation to time. Winter
storms covcr large areas and usually are of low intensity. I n this paper,
results of frequency analyses of one-day rainfalls are presented for all stations
in New Mexico and Arizona, the records of which exceed 15 years in length.
The relation of rainfall frequency to geographic position and topographic
relief are discussed, and recommendations are made for the use of these data
for design purposes.
INTRODUCTION
I n 1935 when the late David L. Yarnell, M. Am. Soc. C. E., published2 an
analysis of rainfall intensity-frequency data, there were only five rainfaI1intensity gages in and near the states of New Mexico and Arizona, the records
of which were sufficiently long to be used in the analysis. That number
represented one intensity gage per 47,000 sq miles. Since then the U. S.
Weather Bureau has launched an extensive program for the collection of
intensity records in these, as well as in other, states, which eventually will
furnish data needed for engineering designs. The data from these newly
installed gages have been published consecutively since January, 1940, and
have supplied basic information for studies of intensity patterns, but the
records are too short for frequency studies.
To help fill the urgent need for detailed recurrence-interval data on rainfall
in New Mexico and Arizona, the present study was made of the records of
rainfall collected by standard nonrecording gages of the Weather Bureau.
NOTE.-Published in February, 1943. Proceedinos. Positions and titles given are those in effect when
the paper or discussion was received for publication.
1 Aviation Cadet, U. S. Army Air Forces, Los Angeles, Calif.
“Rainfall Intensity-Frequenoy Data.” by David L. YarneU, Miscellaneous Publication No. 80.4.
U. 8.D. A. August, 1935.
*
837
838
I
N E W MEXICO AND ARIZONA
I n addition to data on frequency of heavy rainfalls, it usually is necessary,
in the design of certain engineering structures, to assume values of area covered
by the design storm and to determine a pattern of rainfall intensity before a
hydrograph of runoff can be constructed. With these requisites in view, some
data on areal patterns of summer storms and rainfall-intensity records were
included to add to already published data pertinent to the adoption of a
design storm, with particular reference to a small watershed. Due to the
limited areal extent of summer-type rainfall in New Mexico and Arizona, large
watersheds usually are capable of producing the largest floods as a result of
prolonged rainfall covering large areas, or in these states, a typically wintertype storm.
STORM
TYPES
The normal rainy seasons in the Southwestern States are July to September,
inclusive, and December to March. Valley areas usually receive the highest
monthly precipitation in July, August, and September, whereas in the high
mountain areas the greatest monthly precipitation occurs from December
through March, mostly in the form of snow. These seasonal variations in
rainfall amounts are related to storm characteristics and sources of moisture.
Winter precipitation generally is the result of frontal activity associated
with influx of cold air masses, modified Polar-Pacific or Polar-Continental.
Polar-Pacific air picks up moisture from the ocean and moves into the Southwestern States usually as a relatively moist and cool mass that tends to underrun the warmer dry air. If the moist air mass is forced upward over the
mountain ranges, continuous showers or nearly steady precipitation in the
form of rain or snow is recorded over a period of 48 hr or more.
Modified Polar-Pacific air may move into Arizona and New Mexico from
the south, west, or northwest. Invasion from the south or southwest often
results in a relatively stationary east-west front which causes widespread,
low-intensity rainfall in these states. If the moist air comes from the northwest, heavy snowfall may be recorded on the north rim of the Grand Canyon
and on San Francisco peaks, followed by squalls in southeastern Arizona and
southwestern New Mexico.
Polar-Continental air usually comes from the northwest and it tends to
lose its moisture in northern Utah or Colorado. Such air masses are relatively
dry and cold when they reach New Mexico and Arizona, and they do not
constitute an important source of moisture in these states.
The Mogollon Rim, a southwest-facing escarpment extending diagonally
across central Arizona, receives most of its winter precipitation from the
modified Polar-Pacific air masses. This conclusion is borne out by the flood
history of the Gila River which drains the Mogollon escarpment and the
mountainous country of west-central Arizona and southwestern New Mexico.
Generally, high winter rainfalls in the headwaters of the Gila River are preceded
by rain along the southern coast of California.
The source of winter precipitation at least partly explains the fact that
winter storms generally affect large areas which receive rainfall at low intensities for periods of two or three days or even a week. Although, in a
NEW MEXICO AND ARIZONA
839
general way, the total winter precipitation increases with elevation, i t is
influenced to a'great extent by the topographic relief.
These characteristics of winter rainfall contrast with those of summer
rainfall, which ordinarily is not the direct result of frontal activity. Summer
storms usually are of the thunderstorm type with high intensities covering
relatively small areas. Ordinarily the moisture is derived originally from the
Gulf of Mexico and is carried to Mexico by subtropical easterlies where convection causes the warmth and moisture to rise to high levels over the Mexican
Plateau. This air mass is deflected northward and enters the Southwestern
States as a moist tongue a t high levels, crossing the Mexican border usually
west of El Paso, Tex., and east of Yuma, Ariz. Analyses by H. Wexler and
J. Namias3 show that the path of this moist tongue varies from one season
to another, and its position is reflected in the summer rainfall in New Mexico
and Arizona.
The mechanism by which this vapor is precipitated usually is a combination
of convection caused by local heating of the lower layers of air, and orographic
influences of topographic relief. Surface heating of the ground and adjacent
layers of air during a summer day tends t o increase the steepness of the lapse
rate (vertical temperature gradient), and convective instability may result in
local precipitation. This process usually results in instability above a mountain slope more quickly than above a valley plain, because the temperature of
the ground a t the two locations increases at about the same rate. Owing to
the higher elevation of the point on the mountain, the vertical temperature
gradient above that point is greater than that above the valley floor, and i t is
more probable that rain will fall on the mountain slope than over the valley.
Infrequently, sections of New Mexico and Arizona experience a general
summer storm characterized by moderate rainfall over large areas and scattered
local areas of heavy precipitation. Whereas the local summer storms are
mostly of the convective orographic type, the general storm usually is associated
with frontal activity. The effect of topographic relief is relatively small,
although, together with convective lifting, i t may tend to promote local high
intensities in the area of general rain. D a t a on intensities and short-period
isohyetal maps of storms of this type are meager. The most adequate discussion of such a storm is the report of the U. s. Engineer Office on the storm of
August 13-14, 1940.'
Storms of the general type caused the floods of the Pecos and Gila rivers
in September, 1941, the Bill Williams River flood of September, 1939, and the
San Pedro River flood of September, 1926. I n general, the available records
indicate that the average intensities for durations of 1 hr or less are considerably
less in the general storm than in the locz~lsummer storms. I n the former
type, however, the area covered by intense rainfall tends to be somewhat
greater, and the rainfall extends over a longer time period. One of the main
points of difference apparently lies in the importance of frontal activity as a
causal factor.
a "Mean Monthly Isentropic Charts and Their Rclation to Departures of Summer Rainfall." by H.
Wexler and J. Namias, Transactions, Am. Geophysical Union, Pt. I, 1938,pp. 164-170.
4 "Hydrologic D a t a S t o r m of August 13-14, 1940, Arizona and New Mexico," mimeographed
September, 1941, Lo8 Angeles Dist., U. S. Engr. Office, Los Angeles, Calif.
840
NEW MEXICO A N D ARIZONA
Because of the relative infrequence of important storms of the general type,
most of the high rainfalls experienced in 24-hr periods in summer and comprising the point-rainfall data analyzed in the present study may be assumed
to be of the local storm type. Because of the lack of data, adequhte analyses
of the area covered by the different storm types are not included in this paper,
and thus the recurrence-interval data presented subsequently in Tables 2
and 3 are primarily applicable for design purposes to small watersheds.
AREALPATTERN
OB SUMMER
STORMS
The relatively great instability in mountainous country at least partly
explains the areal distribution of summer rains in the basin and range topography typical of many parts of New Mexico and Arizona. Rainfall records
show that summer rainfall in the valley areas and at the base of the mountains
is erratic and spotty, whereas at the crest of the higher mountains the total
summer rainfall tends t o be similar at all points of a given elevation and tends
to increase with elevation. Field observations indicate t h a t in any one
summer storm the center of greatest precipitation usually is near the base of
the mountain slope.
The areal extent of ordinary summer thunderstorms in New Mexico and
Arizona is extremely variable, but the center of high intensity is usually
about 5,000 acres. It is important to note, however, t h a t many storms of
relatively small area occur nearly simultaneously a t widely separated points
within a n area as large as the State of New Mexico. Storms a t any particular
location evidently are associated with relatively widespread instability, or the
influx of moisture into the entire region. Inspection of any monthly summary
of precipitation published in Climatological Data6 shows the regional coincidence
of rainfall, but studies of the storms at any given station demonstrate that the
storms were separate entities of small areal extent.
There is some evidence that the area covered by rainfall in a given summer
storm increases with the total precipitation in the storm center, but only a
few good isohyetal maps of individual storms are available. It appears certain
that the storms occurring in east-central and southeastern New Mexico in the
Pecos River basin cover larger areas than storms in any other section of the
two states, and also any given amount of storm rainfall occurs there more
frequently than in other sections of these states. This presumably may be
attributed to the proximity of the Pecos River basin to the source of summer
moisture, the Gulf of Mexico, and to the fact that the Pecos area sometinies
is subject to the marginal effects of tropical hurricane disturbances that move
into Texas from the Gulf.
Samples bf the depth-area data available for local summer storms are
presented in Table 1. Storm movement and lack of intensity data for various
points within the storm area render this type of depth-area data inadequate
for making assumptions of the depth-area-time pattern for a design storm,
b u t in most sections of the Southwestern States no better data than the samples
1 C l i m ~ t d ~ g i cData,
al
published monthly by the U. S. Weather Bureau.
841
NEW MEXICO A N D ARIZONA
-
TABLE AREA, IN SQUARE
MILES,
COVERED
BY VARIOUS
QUANTITIESOF RAINFALL
(SUMMER
STORMS)
-
Locution
-1
71
3
12
72
I
Date
RAIN, IN INCEIES
71
Pima, Ariz.. ..........
Laa Cruces N. Mex.. ...
Sierra Ancda. Arir ......
Rodeo, N. M e x . . ......
92
a3
Z4
8
............
38
7.2
2.6
b:F; b:i . . . . . . . . .
1
............
55
__-__--____September
August
August
August
16,
29.
5,
13,
132
1939
1935
1939
1940
39
. . . . 5.2
..
.
iii
i:4
11
,
4
.
87
26
Z8
1.5
,
.
in Table 1 are available. A complete report of depth-area-time relations of
storms of these states must await the collection of more records.
RAINFALL
INTENSITY
~
Winter-type storms in New Mexico and Arizona usually produce rainfall
at relatively low intensities. Summer rainfalls of the thunderstorm type
characteristically are intense and of short duration, with tlie period of highest
intensity at, or soon after, the beginning of rainfall. Except in unusual cases,
the periods of high intensity are separated by lulls in the downpour, the period
of uninterrupted intense rain lasting less than one-half hour. I n practically
all cases the intensity decreases more or less gradually to the end of the rain.
Mass curves of the most intense rainfalls on record at recording gages in New
Mexico and Arizona are plotted in Fig. 1( a ) . h h n y summer rains have some
low intensity fall prior to the most intense portion, but in general the curves
i n Fig. l ( a ) are representative of the heaviest rains recorded in the Southwest.
It is important to note the general similarity of pattern of mass curves of
storms from widely separated localities.
From the records of beginning and ending of rainfall observed a t Weather
Bureau stations where standard rain gages are used, i t is possible to collect
additional records of heavy rainfalls of short duration. Fig. l(b) presents the
results of a systematic search through the original records of 162 stations in
New Mexico, comprising 4,656 station-years and certain additional Arizona
records, in an effort to determine the minimum duration of heavy rainfalls.
The key to numbered points is given in Table 2. No rain less than 2.00 in.
or of durations greater than 14 hr is platted, and many 4-in. rains of duration
greater than 6 h r are omitted. The envelope curve drawn in Fig. l(b) indicates
the maximum rainfall of a given duration that might reasonably be expected
in the Southwestern States.
The mass curves of Fig. l(a) indicate the type of intensity pattern that
probably comprised the rainfall totals shown in Fig. l(b), and from these two
graphs an approximate rainfall histogram can readily be taken for purposes of
hydraulic design of engineering structures. It is important to note that none
of t h e rains platted in Fig. l ( b ) occurred in midwinter, and relatively few
occurred outside the season of summer rains, July to Scptember. It may be
surmised from this fact that most of these intense rains covered relatively
small areas, typical of summer-type storms.
842
NHW MEXICO AND ARIZONA
(a) MASS CURV
0
1
2
FIQ.~.-RECORDUO F HEAVY
&INFALL
IN NEW MEXICOAND ARIZONA
(FEOUORIQINALNOTBBos- WBATHBRBUREAUOBUBRVBES)
843
NEW MEXICO AND ARIZONA
Na
-
TABLE KEY
I
Location
TO
Date
Cerro, N. Mex. .......... August
E l Paso, Tex.. . . . . . . . . . . J u l y
AuQuet
L a s Cruces. N. Mex..
Hermosa. N. Mex.. ...... A u i u s t
July
Artesia. N. Mex..
Casn Grande R u i n , A r k August
Solnno, N. Mex..
July
Albuquerque. N. Mex.. ... October
Ione, N. Mex ............ August
W h i t e Sands Nnt’l Monument, N. Mex.. ....... September
11 Crown King, Aris.. ...... August
12 Sierra Ancha. Ariz.. ...... August
1 3 Carnegie Desert Lab., Aria. J u l y
14 Crown King. Ariz.. ...... August
15 T a t u m . N. Mex .......... Sentember
16 Hobbs,.N. Mex.. ........ J u i e
17 E l e p h a n t Butte, N. Mex.. August
August
18 S a n t a Mnrgueritn. Aria.
19 Clovis. N. &lex.. ........ August
20 Diener, N. Mex. ......... J u l y
21 L a s Cruces, N. Mex.. .... September
22 Clovis, N. Mex.. ........ J u l y
23 Obar. N. Mex.. ......... J u l y
24 Ft. Sumner, N. Mex ...... August
25 Corona. N. Mex.. ....... August
26 Mosquero, N. Mex.. ..... M a y
27 Hope, N. Mex.. ......... August
28 S a n t a Rosa. N. Mex.. .... M a y
29 Roy, N. Mex.. .......... M a y
30 Elk, N. Mex..
September
31 Ancho. N. M e x . . ........ J u n e
32 Sierra Ancha. Aria.. ..... September
33 Mnrinette. Aris.. ........ August
34 L a k e Alice, N. illex.. . . . . August
35 S a n Marcial, N. Mex.. ... August
July
36 Lindrith, N. Mex..
1
2
3
4
5
6
7
8
9
10
....
I
.......
.
........
..
..........
......
-
RAINFALLDATAIN FIG. l ( b )
No
-1922
1881
1935
1925
1911
1906
1929
1865
1923
1941
1918
1939
1910
1927
1927
1918
1898
1935
1912
1924
1941
1930
1906
1908
1934
1938
1908
1930
1938
1906
1937
1933
1939
1935
1895
1931
Location
I
Date
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
GO
61
62
63
64
65
66
67
68
69
70
71
72
SEASONAL
DISTRIBUTION
OF HIGH RAINFALLS
A separate analysis furnishes additional information on the seasonal
distribution of high rainfalls. A tabulation was made of all rainfalls exceeding
2.00 in. in a 1-day period for 268 stations in the two states, comprising a total
of 7,048 station-years of record. Stations were grouped into eight general
regions by dividing each state approximately into four quadrants. For each
region, rainfall depths were platted against the day of the year on which each
occurred. An index was thus derived that weights both the frequency and
magnitude of high rains, and is platted for the four regions in New Mexico
and four regions in Arizona in Fig. 2.
The index was derived by dividing the year into periods of ten consecutive
days, and the rainfall magnitude into categories of half inches, beginning with
2.00 t o 2.50 in., 2.50 to 3.00 in., and so forth. For a given 10-day period including all stations, the number of rainfalls t h a t fell in each magnitude category
was multiplied by the average value of the magnitude category, and the sum
of the products times 100, divided by the station-years of record for the region,
was used as the index of magnitude-frequency. For example, in the upper
Gila River and southeastern Arizona area, 35 stations were used, comprising
976 station-years of recobd. Between January 1 and January 10, there were
five rains between 2.00 in. and 2.50 in. in magnitude, and one rain between
5
4
I
(0)
NEW MEXICO;Number of.
Upper Rio Grande watershed and northwestern New R l e x ~ c o
Lower Rio Grnnde watershed and bouthuestern New Memco
Canadtan River watershed and northeastern New Mexico
Pecos River watershed and Southeastern New Mexico
F I G . 2 . 4 B A 0 O N A L VARIATION O P
Stations
37
25
39
47
Station-yeaw
925
aoz
1.068
1.227
RAINFALLFREQUENCY (MAQMTWD~
11
10
9
8 aUl
e
3
72
I
6 $
0
e
LL
5 %
x
U
4
-
3
2
1
0
10
9
8
7 U
0
e
6 G
?
)
.
5 5
m
t
LL
4 %
x
w
3 -
2
1
December
10 20
(b)
ARIZONA:Number of:
Stations
Bl
a
INDlX
Verde River watershed and northwestern Arizona
Lower Gila River watershed and southwestern Arizona
Little Colorado River watershed and northeistern Arizona
Upper Gila River watershed and southeastern’Arisona
DBRIVFAD
FROM
RAIN8 EXCHl6lDINQ
2.00 IN.
IN ONFA
DAY)
Station-years
I
I
43
0
958
671
846
NEW MEXICO AND ARIZONA
5.50 in. and 6.00 in. T h e index platted a t the midpoint of the period January
(1 X 5.75) =
1 to 10 was 100 X (5 X 2.25)
+
976
It was necessary to divide by the number of station-years of record to
make the computed indexes of the various regions comparable for platting,
and the multiplication b y the arbitrary value 100 was simply for the purpose
of making the platted indexes whole numbers to facilitate platting and
comparison.
The platted indexes in Fig. 2 show that the eastern section of New Mexico
experiences high rainfalls more frequently than the western section of the state;
but all sections receive high rainfalls predominantly in the summer and fall
seasons, whereas November through March is comparatively free of heavy
rainfalls. The heaviest rainfalls in western New Mexico occur between the
first of July and the middle of August, and again in mid-September.
I n Arizona, however, all regions except the northeast quadrant have a
high index in summer, whereas in winter only the southeast and northwest
quadrants have high indexes. These differences can be explained by the
relation of topography, geographic position, and source of moistute. It was
stated previously that summer moisture originates in the Gulf of Mexico
and moves into New Mexico and Arizona primarily from the south, and that
the Pecos Area in southeastern New Mexico sometimes is affected by tropical
disturbances that cause great rainfalls in southern and central Texas. It may
be expected, therefore, t h a t the eastern section of the state would experience
more high rains than the western because of the proximity t o the source of
moisture.
The southwestern section of New Mexico has a higher frequency-magnitude
index than the northwest, since the latter is in the rain shadow of the mountainous southwestern section.
The index for regions in Arizona in summer is highest in the mountainous
southeast and northwest quadrants, which can be related t o the effect of
topography. The index for southwestern Arizona is high in midsummerJuly and August-because of the convective storms that are common over the
desert a t that season. Northeastern Arizona is on the plateau in the rain
shadow of the Mogollon Rim and the mountainous central belt, and probably
for this reason the index is low.
I n winter, when moisture is derived from the Pacific Ocean and moves in
primarily from the Southwest, the frequency-magnitude index should be high
only for the mounttlinous sections of Arieona, the southeast and northwest
quadrants, and relatively low in other areas and in New Mexico. The present
study supports this hypothesis.
FREQUENCY
OF HIGH RAINFALLS
Recurrence-interval curves were drawn for each standard rain-gage station
in New Mexico and Arizona whose records exceed 15 years, and for certain
stations of shorter record, in order t o derive values of 24-hr rainfall that may
be expected to be equaled or exceeded in a given period of years. These
data are useful in the design of engineering structures, especially where it is
NEW MEXICO AND ARIZONA
847
necessary to design for a rain greater than has been experienced in the past.
The data also indicate the recurrence-interval of rainfalls t h a t have occurred
in the past.
I n this analysis the highest one-day rainfall in each year of record at t h e
station was tabulated, the data arranged in order of magnitude, and the curve
platted by the “exceedance interval,” or “California,” method. From the
platted curves, the 24-hr rainfall t h a t probably will be equaled or exceeded
in 5, 10, 15, 20, 35, 50, 7 5 , and 100 years, was tabulated and the data are
presented in Table 3 ( a ) for New Mexico stations and Table 3(b) for Arizona
stations.
The rainfall data used were recorded by standard nonrecording rain gages
maintained by the Weather Bureau. The rainfall depths were taken from
the original records on which, in about half the cases, lthe observer had noted
the time of beginning and time of ending of the precipitation. By use of these
notations of times i t was possible to ascertain the greatest rainfall in a 24-hr
period, which was the value used in the frequency array wherever possible.
Particularly in the case of summer rain, the precipitation often starts in midafternoon and ends during the night, which is a period of less than 24 hr.
Many observers read the gage a t sunset; so, in the foregoing example, if no
rain fell on the day following, the sum of the two sunset readings equaled the
amount that fell in a 24-hr period. Rains continuing through two or more
days could not be broken down accurately to determine the largest amount
in a 24-hr period and, therefore, the largest amount recorded for one day was
used in the recurrence-interval array. The method used approximates,
closely, the actually greatest fall in a 24-hr period, since a large percentage of
the high rains fell in summer and lasted less than 24 hr.
The characteristics of summer and non-summer precipitation were considered sufficiently distinct and important t o warrant separation in the recurrence-interval determinations. Arrays were made separately for the highest
rainfall recorded each year between June 1 and September 30 (the summer
period), and the highest rain recorded in each complete year. Certain stations
may be expected to experience the same 24-hr rainfall at a given recurrenceinterval in summer as they will experience in the entire year as can be seen in t h e
tabulations of 50, 7 5 , and 100-yr frequencies. This simply indicates that t h a t
station characteristically received the largest 24-hr rainfalls in the summer
period and, therefore, the recurrence-interval curves for summer and all year
would be practically identical.
Winter values of rainfall amounts probably are somewhat less accurate than
summer values owing to the effect of snow. One source of error was the failure
of a gage to catch the full snowfall, but probably a more important error was
introduced by the general policy of assuming that 1 in. of snow equaled 0.10 in.
of precipitation in the form of water. Investigations by the Weather Bureau
indicate that, in particular instances, much larger’ amounts of precipitation
were assumed by the use of this policy than actually fell.
The compilation of a recurrence-interval array necessarily involves some
exercise of judgment. I n many cases, particular months were missing from a
848
N E W MEXICO A N D ARIZONA
TABLE 3..
FREQUENCY
(Data from Records Pub
I
No
Eleva-
.
Station
tlon
(feet)
Averae
annual
preclpltation
through
1939
l
l
h:vh
AVXXUQB01
RWORDUWD FOR PRBQU~NCY
ARRAT
ggz)
(Lnohea)
.
6.767
5,590
Fruitland ............
3
Farmington ..........
Bloomfield...........
Aaynea . . . . . . . . . . . . .
Tohatchi ...........
Crownpoht ..........
Gamerco ............
10 Pt . Winnate .........
11 McCaffey Ranger
Station ............
12 Bluewater. . . . . . . . . .
13 Ramah ..............
14 San Fidel ............
15 Black Rock ..........
16 Chama ..............
17 C a m ...............
18 Red River Canyon ....
19 Tres Piedras . . . . . . . . .
20 Aspen Grove Ranch ..
21 Ea& Rock Ranger
Station ............
22 Bateman's Ranch .....
23 Taoe Canyon ........
24 Taos ................
25 Truchas .............
26 Espanola ............
34
38
5, .65
6.68
35
5 ,220
5,500
6.600
6 ,800
6.800
6.785
8.997
8.35
8.79
11.80
11.07
11.15
11.94
14.45
25
41
16
24
26
22
48
8.000
6.732
7. 200
6. 100
6.455
7. 851
7. 668
8.956
8.076
9.000
17.77
in.28
13.68
10.37
12.29
22.10
13.98
21.65
16.05
23.38
27
34
15
20
31
44
29
34
40
31
1916-1939
1897-1902; 1909-l917; 19261939
1923; 1924; 1927-1939
8.000
8.900
8.959
8.983
7.936
5.590
15.70
23.48
19.52
12.61
15.55
9.9G
17
31
31
47
31
35
1914-1930
1910-1939
WIO
22.19
18.13
15 38
18.07
22.13
17.60
14.39
28
29
I6
30
16
13
90
29
30
69
Selsor Ranch . . . . . . . .
Alamos Ranch .......
Frlioles Canvon ......
Lee's Ranch .........
Santa Pe Canyon .....
Santa Fe ............
7.328
6. 200
6. 100
8.691
8. 100
6.994
34
35
Stanley .............
Alhuquerqiio .........
6.317
5. 314
12.20
8.18
36
Laguna .............
5.840
11.14
37
Estancia ............
6.300
15.14
26
38
39
MoIntosli ...........
Loa Lunns ..........
6.355
12
4.900
13.04
8.4G
61
20
40
41
Tajiqrie .............
Mountainair .........
7. 100
6.475
19.68
16.03
33
42
43
Datu ...............
7. 85.0
8.556
13.22
12.68
28
37
44
Sooorro .............
4. 600
10.19
53
46
Sun Marcia1 .........
4. 447
9.11
83
46 Glorleta Rnnoh .......
41 Clibrlda Ranger
Station .............
6.300
11.88
23
19
6. 500
14.84
Magdalenu ..........
.
I
_.
18.13
9.06
27
28
29
30
31
32
33
#JemezS p r i n b........
year8
.
.
.
1 Dulce ...............
2 Aztec ...............
4
5
6
7
8
9
Data (lncludve)
-
MAXIMUM
1-DAYRam
E~ca:
1900-1915; 1917-1939
1895-1901; 1911-1918; 191g1923; 19251939
1893; 1895; 1897; 1904-1915; 1917-1922;
1939
1914-1930; 1933-1939
1905-1939
1910-1917; 192C-1926
1915; 1918; 1923; 1926-1927; 1929-1939
1914-1919; 1921-1939
19221939
1897-1910
NBI
.
33
34
1.16
.91
1.34
1.01
22
.79
.95
24
35
15
16
25
18
14
..87
90
1.16
1.13
1.05
$1
1.23
.94
.97
1.20
1.19
1.11
1.12
1.44
1.10
1.06
1.36
1.20
1.01
1.07
1.20
1.02
1.11
1.10
1.41
1.20
1.68
1.22
1.10
30
31
41
31
31
1.07
1.24
1.04
.93
1.14
1.04
1.22
1.46
1.22
1.08
1.29
1.14
28
27
16
30
16
13
83
1.30
1.34
1.54
1.49
1.89
1.14
1.15
1.46
1.57
1.66
1.63
2.08
1.26
1.29
a7
63
1.32
.95
1.39
25
1.27
1.48
19
1.21
1.35
12
44
1.28
1.16
1.53
1.31
29
31
1.47
1.45
1.78
1.70
28
30
1.19
1.14
1.27
1.31
189jIi894;1896-1897; 1899-1901; 1904-
43
1.19
1.38
1939
1895-1899; 1901; 1904-1900; 1912-1919;
1921-1939
1910-1928
39
1.17
1.38
18
1.10
1.40
18
1.26
1897-1898: 1910-1939'
24
29
15
20
29
37
28
32
33
32
17
1m-im
.
.......
1893-1895; 1902-1939
1905; 1909; 1910-1916: 1918-1939
1S95-1900; 1902; 1905; 1007-1909; 19111918; 1920-1929; 1938-1939
1S94; 1912-1926; 1928-1939
1911-1916; 1918-1920; 1922-1939
1924-1939
1910-1930
1939
1905-1907: 1900-1911; 1913-1917; 19231927; 1937-1939
1928-1939
1893-1897; 1899-1901; 1903-1909; 19111939
1910.1918 . 1920-1939
1902-1915; 1917; 1919-1921; 1923; 19281939
1906-1008; 1818-1924; 192fI-1939
1905-1915; 1918-1925; 1927-1931; 1934-
.
1W70
1.40
1.93
1.19
1.28
1.40
1.13
1.49
.
-
L
1 Average of the maximum I
'Average of the maximum 1
by raln rsaorde
y rain reoorda
Dr th
ldlo
NEW MEXICO
-
- -
- - - -
-
- - - - __
1.40
1.92
1.25
2.00
1.00
!.02
5.00
2.19
!.lo
5.60
1.28
1.12
2.18
1.34
2.35
!SO
2.50
3
1.50
1.78
1.86
5.50
2.30
2.50
1.00
4
5
9
10
i.60
1.60
1.00
1.31
3.50
3.50
3.60
2.55
3.10
4.10
6.60
2.60
3.00
4.12
11
12
13
14
15
16
17
18
19
20
1.65
1.35
.75
.48
:20
..59
.06
.GO
!.GO
2.0
.G9
!.90
.70
.80
1.91
1.83
.G5
.98
1.24
.40
1.51
.58
.66
.70
.78
1.96
'.OO
!.50
1.16
1.92
1.43
1.75
2.77
4.95
2.23
2.47
3.77
1.70
1.80
i.50
1.30
1.00
1.70
3.11
3.00
3.35
2.40
2.69
3.32
4.30
2.31
2.62
3.61
1.63
1.40
1.41
1.88
1.80
1.40
1.95
3.36
3.30
2.83
1.26
3.48
2.50
2.90
3.75
5.00
2.48
2.85
3.90
1.71
1.50
1.50
1.89
?.lo
1.74
1.20
1.46
1.31
1.50
1.28
3.25
1.85
1.67
2.28
2.20
2.29
2.60
2.16
1.88
1.81
1.62
1.92
1.70
2.59
1.02
1.87
2.31
1.92
1.70
2.62
1.91
1.89
2.78
2.00
1.74
2.69
2.11
1.92
2.40
2.01
1.74
2.75
1.98
1.92
2.90
2.05
1.78
2.75
2.20
1.99
1.50
1.10
1.78
2.82
1.00
1.99
3.00
2.10
1.80
2.82
2.28
21
22
23
24
25
26
2.52
2.91
3.25
2.83
3.43
2.19
2.58
1.68
1.70
3.35
3.25
3.79
2.21
2.98
2.70
3.19
3.46
2.99
3.52
2.30
2.81
2.80
4.11
3.60
3.41
3.90
2.30
3.39
2.89
3.46
3.65
3.1C
3.GC
2.4(
3.1:
2.93
4.60
3.89
3.63
4.10
2.40
3.95
3.00
3.68
3.80
3.20
3.70
2.50
3.40
3.05
4.95
4.10
3.80
4.20
2.50
4.50
27
28
29
30
31
32
.33
2.59
3.02
2.85
3.35
2.85
3.95
3.09
3.89
3.09
4.69
3.3:
4.5(
3.33
5.45
3.50
5.00
3.50
6.00
34
35
1.99
2.69
2.06
3.00
2.10
3.28
2.11
3.53
2.17
3.75
36
2.45
2.45
2.71
2.71
2.90
2.9@
3.1(
3.10
3.21
3.21
37
2.58
2.15
2.50
2.10
2.78
2.21
2.93
2.23
3.12
2.35
3.25
2.31
3.4@ 3.61
2.41 2.4(
3.70
2.50
3.89
2.48
3.90
2.57
38
39
2.60
2.46
2.79
2.65
2.80
2.61
2.97
2.78
3.18
2.90
3.30
2.99
3.45
3.11
3.51
3.15
3.7'
3.3
3.79
3.35
4.00
3.43
4.00
3.49
40
41
1.7:
2.0:
1.81
1.7E
1.82
2.19
1.90
1.82
1.90
2.29
2.02
1.90
2.02
2.44
2.11
1.95
2.11
2.57
2.2'
1.91
2.21
2.68
2.30
2.00
2.30
2.76
42
43
2.5!
2.41
3.10
2.71
3.51
3.37
4.50
3.87
5.15
4.51
6.2C
5.00
7.00
44
3.50
4.30
4.44
5.00
5.U
6.01
6.0C
6.70
6.70
45
46
1.20
1.68
2.65
1.17
.92
1.85
.78
1.60
1.41
1.05
1.15
!.21
!.92
!.77
1.22
!.30
.99
1.79
2.54
2.37
2.12
3 10
1.81
2A2
2.17
3.58
2.10
2.41
2.05
1.72
1.40
1.82
1.65
2.46
1.91
1.80
2.21
1.85
1.56
2.51
1.30
1.58
1.00
1.64
1.30
1.00
1.21
2.48
3.18
3.00
2.97
3.51
2.07
2.48
2.41
2.63
1.57
2.60
1.94
2.50
2.35
2.35
2.3'
2.04
2.30
2.01
2.38
2.28
2.51
2.41
1.51
1.71
1.71
1.7C
1.8
2.0:
.69
.57
1.20
1.70
.82
.70
.93
1.71
1.58
1.20
1.70
1.85
1.16
1.53
.80
.60
.31
1.88
1.64
2.40
1.70
1.51
1.70
1.62
1.51
1.60
1.98
1.90
1.25
1.01
2.75
1.92
1.89
2.08
2.22
1.78
1.89
2.42
!.05
..81
!.73
,.72
..98
!.89
!.42
1.75
1.00
1.82
1.46
1.25
1.91
2.06
1.08
1.33
1.65
1.90
1.06
1.70
1.49
1.85
1.55
1.39
1.91
1.5C
1.57
1.63
1.99
1.65
1.53
1.22
1.72
1.69
2.30
1.78
1.61
2.37
1.83
..70
1.55
1.48
1.05
1.65
1.61
2.14
1.G9
1.55
2.24
1.71
1.71
1.59
1.32
1.79
1.9t
2.01
2.18
2.1g
2.8:
1.6:
1.U
1.00
1.18
2.62
2.38
3.04
1.80
1.83
2.21
2.51
2.6:
2.61
3.21
1.81
1.9:
1.18
1.40
2.80
2.51
3.20
1.91
2.05
2.36
2.90
2.80
2.80
3.40
1.98
2.22
1.9(
1.5(
2.17
1.89
2.2:
2.11
2.40
2.28
1.9(
1.88
2%
1.81
2.15
2.1:
1.9:
1.71
2.02
1.91
2.11
2.11
1.91
1.71
1.60
1.81
1.72
1.88
2.4(
1.6!
.e5
.91
.78
.04
1.11
38
!.12
..91
!.OS
1.00
2.00
2.20
2.90
!.50
1.00
4.30
2.48
2.50
2.Gl
2.9C
3.11
3.35
1.91
1.81
2.02
1.95
2.11
2.15
2.30
2.30
2.4(
2.4.
2.51
2.58
2.6C
2.2
1.N
2.48
1.9E
2.69
2.07
3.03
2.12
3.3(
2.21
3.G(
2.24
3.8C
1.81
1.81
-
- 3pte
1
2
2.38
1.05
.70
1.50
1.78
!.08
!.35
1.14
1.58
1.50
1.05
1.31
1.72
1.01
1.28
!.OO
.50
1.38
1.68
177
1.95
2.23
1.98
2.60
1.02
1.65
1.50
3.78
2.05
1.89
2.28
51
.49
1.05
1.31
.71
.60
..78
1.55
1.68
1.78
1.74
- - -
2.20
1.71
2.65
4.30
2.16
2.50
3.42
,.82
.61
!.31
1.05
1.92
1.22
1.72
1.29
1.30
1.73
1.70
1.50
1.70
1.86
L.68
849
AND ARIZONA
ir
31
- each year
01
record.
- - - -
-
- - -
6
7
8
47
-
No .
Station
Elevatlon
(feet)
Average
annual
preripi- Le:fth
tation
): : : : ; ;
throunb
1939
(inches)
RECORDUsao
FOR
FREQLENCY
A
Dates (inolusive)
.
.
48 Hermosa ............
49 Elephant Butte ......
7.200
4. 265
17.79
9.91
15
55
50 Kingaton ............
51 Hillsboro ............
6. 500
5.236
18.18
12.81
25
34
52 Garfield .............
4. 100
1n.m
33
53 Lake Vnlley .........
54 Jornada Experimental
Range ............
55 Deming .............
56 Las Cruces
(Acrioultural College
57 Cambray. ...........
58 Newman ............
59 Lanark ..............
5.412
13.41
33
1914-192G
1SQB-1904;1908-1916;1918-1921;19231938
1916-1039
1896-1900;1904-1909;1911;1925-1933;
1935-1939
1894-1899;1905-1917;1920-1923;1925;
1927
1905-1923;1927-1939
4.150
4.331
9.28
9.66
26
64
1914-1939
1893-1039
26
47
1.05
1.15
8.66
8.92
83
39
24
9.58
13.79
31
31
1892-1939
1899-1933;1936-1939
1909-1932
1899-1918;1921
1909-1039
1900-1902:1906-1907;1989-1921;19331927;1930-1938
1003-1906;1008-1918;1920-1939
1910 1939
189~-iooi;
19n3-1905:1910-1925
1895-1000;1005-1910:1912-1914; 1916;
I93 1 1939
1911-1932;1934-1039
1905-1919;1930-1939
1897-1919: 1921-1939
1901;1912-1939
1905-1939
1S93-1939
1909-1039
1900-1039
1900-1911; 1913-1939
ion4-i9zo;1024-1825
1895-1906;1909;1912-1939
l'Jl(i-1039
1909-1939
1905; 100s-1931
1904-1930
1896-1899;1909-1911 ; 1913-1939
1893-1894;1896-1897;1900-1001;1904-
48
39
24
21
31
32
1.11
1.16
1.29
1.14
1.25
1.03
35
24
27
25
1.09
1.01
1.12
1.44
28
25
42
1.48
1.35
1.38
1.46
1.32
1.10
1.34
1.29
GO
61 Horse Springs........
Columbus . . . . . . . . . . .
3.909
4.225
3.989
4.156
4.051
7.070
62
63
64
65
Luna Ranger Station ..
Hood Ranger Station .
Alma ...............
Cliff (Gila) ..........
7.300
5 .838
4.800
4.470
16.18
14.19
14.89
14.22
40
23
26
32
66
Pinos Altos ..........
Mimbrea ............
Ft . Bayard ..........
Gilver City ..........
Redmck.............
Imdsbnrg ...........
Hachita .............
Rodeo ..............
Lake Alice ...........
Vermejo Park ........
Raton ..............
Des Moinea ..........
7.000
6.260
6.152
5.937
4.150
4.245
4.504
4.118
6.950
7.600
6.660
6.622
6.396
22.89
29
2G
71
67
68
69
70
71
72
73
74
75
76
77
78
79
80.
81
82
83
84
85
86
87
an
89
90
91
92
93
94
95
Dnwson .............
Maxwell. ...........
Ciarron ............
Clayton. ............
Springer .............
Mlami ..............
Taylor .........
Pasamonte .....
Black Lake ..........
Abbott ..............
Pnlo Verde ..........
Pt . Union ...........
Solano ..............
96 EIoosier Ranch .......
97 Valmora ............
on hlosquero ...........
99 [one ................
in0 Bell Ranch ..........
101 Dbar . . . . . . . . . . . . . . . .
102 Trementinn ..........
103
Logan . . . . . . . . . . . . . .
1W Tuoumcari No . 1 . . . . .
9.05
8.20
25
13
40
24
26
1.75
1.38
1.59
1.48
25
1.54
32
1.52
~
16.33
15.70
17.38
12.30
9.57
10.76
11.04
19.85
17 13
15.61
37
35
59
30
31
31
19
44
17.23
24
15.54
31
27
36
35
51
5.894
1-1.53
15.56
15.62
14.18
6.000
5 .661
6 .650
8.348
8.849
15.73
15.57
15.11
16.21
20.45
15.28
14.98
20.38
17.24
15.97
15.18
32
31
30
29
31
18.01
02
6.427
5.049
5.857
29
35
47
31
31
30
19
40
21
31
25
38
34
42
14:m
4.825
5.771
8.510
6.252
5.880
5.884
6.885
5.G22
5.680
0.200
5.579
4. 850
5.400
4. 225
32
24
30
31
31
29
19fJ8Li917;1919-1028;1928-1939
1909-1932
1910-1939
1909-1939
1809-1939
1911-1030
1909-1930
30
24
30
31
31
29
31
31
28
1932-1939
28
31
23
31
29
21
25
24
41
30
-1918
5.000
16.71
15.40
16.51
16.02
16.57
15.24
16.36
15.68
91
29
22
25
30
41
3i
3.851
22
191.I-1923:192G-1939
1920-1028
1G.29
20
31
4. 100
1921-1037:1939
16.35
33
35
1926-1939
.
35
.
1.421
1.25
1.75
1.64
1.44
1.40
1.30
1.49
1.44
1.47
1.20
1.57
1.33
1.45
1.87
1.59
1.20
1.68
1.30
1.55
1.71
1.89
1.80
1.52
1.78
2.19
1.62
1.80
1.52
1.85
1.74
-
y rrin reeorde
i
rain recordet
851
NEW MEXICO AND ARIZONA
__
No.
- - - - - - -
- -
-
- - __
2.25
1.75
1.10
.81
1.95
1.29
1.85
!.38
3.41
2.67
.28
!.70
3.80
2.95
.55
1.00
1.55
3.60
5.15
3.60
i.10
1.06
5.50
1.06
1.60
5.95
LBO
6.30
5.00
5.30
5.00
48
49
2.10
1.98
!.30
L.00
1.52
2.32
!.73
!.34
2.80
2.55
!.97
!.55
2.99
1.68
1.13
!.68
3.35
1.97
3.50
2.97
3.64
1.12
3.78
3.12
3.95
1.34
4.00
3.34
4.20
3.50
1.20
3.50
50
61
1.70
1.71
1.91
1.91
2.00
!.OO
2.05
!.05
2.15
2.15
1.20
2.20
1.26
2.26
2.30
1.30
52
1.90
1.98
2.49
1.61
2.90
t.95
3.22
1.29
1.00
4.03
130
4.60
5.40
5.40
6.00
5.00
53
1.40
1.65
1.53
1.70
1.76
1.84
L.81
1.91
1.96
1.92
1.00
1.99
2.12
1.98
!.17
L.01
2.45
2.02
2.46
2.08
1.68
2.05
2.71
2.10
1.95
1.06
2.97
2.13
3.20
2.08
3.20
2.12
54
55
1.45
1.59
1.63
1.65
1.75
1.33
1.55
1.74
1.66
1.65
1.80
1.55
1.99
1.89
1.88
2.02
2.20
1.50
1.09
1.01
1.90
1.02
1.21
1.76
2.36
2.04
2.00
2.30
2.48
1.60
1.46
1.11
1.03
1.30
1.50
1.88
2.68
2.13
2.12
2.44
2.68
1.66
L.76
1.21
1.15
!.44
1.69
1.98
3.35
2.35
2.33
2.80
3.10
1.80
3.40
2.39
2.35
2.80
3.10
2.10
3.88
2.49
2.47
3.05
3.40
1.89
3.98
2.51
2.50
3.05
3.40
2.20
1.50
1.60
1.60
3.35
3.75
1.97
4.58
2.62
2.63
3.35
3.75
2.30
5.00
2.70
2.70
3.58
4.00
2.01
6.00
2.70
2.70
3.58
4.00
2.38
56
57
58
59
60
61
1.41
1.35
1.40
1.81
1.68
1.52
1.68
2.10
1.68
1.53
1.59
2.19
1.92
1.70
1.92
2.38
1.82
1.62
1.69
2.31
1.06
1.80
1.08
1.50
1.94
1.68
1.78
2.41
1.19
L.89
1.18
t.59
2.18
1.78
1.90
2.64
2.35
2.03
2.37
2.75
2.32
2.50
1.90
1.99
2.79
2.50
2.11
2.50
2.85
2.62
1.92
2.lZ
2.90
2.64
2.20
2.65
2.95
3.00
2.76
2.29
2.78
3.01
62
63
64
65
2.30
2.25
2.49
2.22
2.05
1.98
2.60
2.30
2.50
2.20
3.65
3.25
2.68
2.62
2.70
2.73
2.50
1.40
1.41
1.62
1.25
1.60
2.18
2.75
2.45
3.30
2.3a
3.85
3.30
3.00
3.02
3.35
3.3c
2.7C
2.41
2.38
2.70
2.30
2.13
2.11
2.79
2.41
3.66
2.31
4.01
3.40
2.91
2.83
3.00
2.99
2.71
1.50
1.52
1.81
1.31
1.79
1.34
1.93
2.52
3.53
2.40
1.20
3.45
3.21
3.20
3.60
3.59
2.89
2.60
2.60
3.10
2.38
2.29
2.43
3.10
2.60
3.00
2.55
4.85
3.63
3.43
3.25
3.60
3.45
3.15
2.69
2.70
3.20
2.45
3.09
2.68
3.28
2.68
4.10
2.60
4.95
3.65
3.65
3.50
4.12
4.20
3.25
2.78
2.75
3.41
2.42
2.39
2.63
3.32
2.70
3.21
2.70
5.48
3.78
3.80
3.51
4.08
3 80
3.48
2.80
2.82
3.50
2.51
3.30
2.90
3.50
2.79
4.43
2.72
5.59
3.80
4.00
3.70
4.49
4.70
3.50
2.90
2.90
3.80
2.48
2.40
2.88
3.60
2.83
3.50
2.88
6.20
3.90
4.25
3.85
4.60
4.20
3.80
2.90
2.98
3.80
2.60
3.55
3.40
3.78
2.85
4.85
2.88
6.30
3.95
4.35
3.90
4.85
5.20
3.80
3.00
3.00
4.00
2.50
2.58
3.05
3.80
2.90
3.70
3.00
6.80
4.00
4.60
4.10
6.00
4.50
4.00
3.00
3.09
4.00
2.68
3.70
3.40
4.00
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
2.35
1.95
2.80
2.10
2.85
2.92
3.18
1.95
2.58
2.40
3.00
2.80
3.40
3.65
2.46
2.55
4.95
2.6C
3.52
3.45
3.36
3.0s
2.8E
2.0(
3.3E
2.1f
3.4(
3 3
3.45
2.3:
2.8:
3.3
3.9(
2.8:
3.7:
4.9!
2.71
3.01
5.1(
3.21
4.1(
2.47
2.00
2.93
2.15
3.16
3.10
3.40
2.09
2.70
2.57
3.27
2.90
3.71
3.90
2.61
2.65
5.40
2.78
3.89
3.09
2.05
3.M
2.21
3.61
3.x
3.71
2.4:
2.95
2.51
4.31
2.91
4.1(
5.3
2.81
2.68
2.09
3.18
2.22
3.80
3.40
3.90
2.33
2.98
2.88
3.80
3.05
4.40
4.40
2.90
2.80
6.30
3.10
4.65
4.40
3.70
3.40
3.50
2.11
4.18
2.25
4.15
3.56
4.30
2.70
3.15
4.05
5.2C
3.OE
4.76
2.81
2.12
3.31
2.27
4.27
3.59
4.28
2.50
3.16
3.09
4.19
3.12
4.99
4.78
3.11
2.91
7.00
3.32
5.22
3.80
2.17
4.59
2.29
4.50
3.70
4.69
2.89
3.29
4.40
5.84
3.12
5.30
6.80
3.30
3.77
7.10
4.28
5.62
4.90
3.85
4.23
2.93
2.18
3.48
2.29
4.80
3.79
4.60
2.70
3.35
3.30
4.70
3.22
5.60
5.15
3.30
3.05
7.70
3.60
5.95
5.40
3.95
s.75
4.13
2.18
5.00
2.29
4.90
3.00
2.20
3.60
2.30
5.20
3.90
5.00
2.84
3.50
3.50
5.00
3.30
6.20
6.40
3.50
3.10
4.30
2.20
5.38
2.30
5.20
4.00
5.40
3.20
3.50
5.00
7.20
3.30
6.20
1.90
1.78
1.80
1.90
1.70
1.43
1.94
1.80
1.80
1.73
2.40
2.45
1.88
1.90
1.76
1.95
1.82
1.90
1.65
2.21
1.80
1.90
2.21
2.20
1.51
2.05
1.87
2.10
2.34
2.4C
2.6E
1.95
2.2c
8.3E
2.03
2.4(
2.H
2.72
2.4:
2.05
2.00
1.98
1.92
2.00
1.61
2.07
2.03
2.41
1.W
2.6E
2.61
2.2€
2.24
2.3:
2.31
2.0:
2.15
1.7!
2.3f
1.9:
2.41
2.51
2.5(
1.8:
2.3:
2.5:
2.61
2.4:
2.6!
3.4!
2.21
2.41
3.5(
2.41
2.9!
2.5:
2.81
2.71
2.15
2.08
2.21
2.11
1.92
1.77
2.39
2.13
2.28
2.01
3.19
3.00
2.38
2.37
2.31
2.45
2.28
2.30
2.20
1.88
2.61
2.03
2.49
2.69
2.82
1.80
2.39
2.20
2.65
2.08
3.00
3.30
2.27
2.42
4.3c
2.4C
3.11
2.9L
3.15
2.60
1.93
3.00
2.10
3.04
3.00
8.09
2.13
2.70
3.09
3.38
2.8E
2.29
2.39
2.13
2.40
1.98
2.50
2.32
2.97
2.17
3.40
3.10
2.71
2.78
2.95
2.90
2.43
2.70
3.30
4.41
2.53
2.87
4.50
2.99
3.69
3.10
3.25
3.15
- - -
3.61
3.80
3.4:
3.41
3.49
3.2C
- - - - - perio
year
me
eC0
-
#eptember30 in each year of record.
3.2f
5.52
3.3
4.4!
3.8(
3.5:
3.61
6.2(
3.1(
3.5E
6.4(
3.9:
5.M
4.4(
3.7:
3.N
- - -
1.84
4.00
3.80
3.68
-
-
i.80
2.08
3.88
5.10
3.08
3.40
4.75
6.70
3.22
5.85
7.50
3.45
3.97
7.90
4.65
6.3C
5.4c
3.9:
4.5:
8.30
3.80
6.50
5.78
4.00
3.82
- - -
2.00
5.10
3.00
6.80
4.00
4.60
4.10
5.09
5.60
4.00
8.00
3.60
4.10
8.40
5.00
6.80
5.78
4.0C
4.8C
a?
a4
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
- -
,
No.
Station
Elwatlou
(feet)
Average
annual
precipitatioo
through
1939
Cinohea)
AvmRnam OF
&CORD
U S l D FOB h Q U Q N C Y ARRAY
","f""
EACE:
Dates (inoluaive)
Number Sum-
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
-
-
.. . .
Montoya . . . . . ... , 4,335
fJan Jon. . . ...... ...._ 3.982
8,800
9,400
Onava . . . . . . .. . . . . . . . 6,700
Gallinas Plant. Station, 7,500
7,050
6,400
6,900
Doretta . . . ... .. .. . 6,381
Cuervo.. . . . .. . .
4,849
Palma, , . . . . .. . .
7,000
4,624
Pastura. . . . . .. ... . . . , 5,285
Vaughn. . . . .. . . . . , 5,930
4,500
Ft. Sumner . . . . . . . . , 4,028
Durnn . . . . . . . .. . . . . . 6.272
4,400
4.250
4,262
6,433
Corona. . . ..
. ... . 6,666
Portalea. . . . . .. . . . . .. , 4,004
WMS
Ranger Station 6.636
Eli
4,345
An
6.112
Kichland. . . ... . . . . . 4,000
Bonz . . . ... . . . .. .. .. .. 4,154
5,438
6,700
6,348
6,231
. ...
14.06
15.69
24.49
33.43
15.78
25.64
21.06
17.77
15.99
15.79
13.26
11.78
14.28
12.69
13.01
14.34
15.55
14.23
16.28
16.57
18.30
12.89
14.77
17.55
14.26
15.04
12.47
14.51
13.16
13.42
19.54
17.11
15.96
24
33
45
15
32
25
20
56
22
21
31
26
40
4.436
7,000
Tntum. . . . .. . . . . . . . . . 3,950
Meacalcro . . . . , . . .
6,627
Prairieview. . . . . .
3,825
Tularosa. . . . . . . , . . . .. 4,436
Cloudcroft. . . .. . .. . . . . 8,R50
Elk. . . . . . . . . . . .. . . . . , 5,350
Lovington. . , . . . .. . . . . 3,900
14.38
9.56
22.88
15.75
19.46
15.11
9.32
24.56
17.42
14.37
31
31
22
38
25
32
28
29
19
31
33
31
27
30
27
31
32
17
31
66
19
62
24
56
21
28
28
32
38
33
32
Mountain Park. . . . . , ,
Mnybill Ranger Station
Alnmogordo. . . . . . . . . .
Artwia.. . . . . . . . . . , , , .
Weed Itongcr Station . .
Hope . . . . . . . .. . . . . . .
Hobbrr. . . . . .. . . . . . . .
18.42
19.63
11.18
12.29
21.27
13.63
15.45
25
23
45
33
15
21
22
10.95
11.74
12.83
9.43
10.94
19.29
17
26
48
33
22
26
.
.
l-%xm
..
..
. . ...
..
5,016
Roswell . . . . ..... . ... . 3,002
.
6.720
6,400
4,338
3,350
7.200
4,000
3,FOO
Pearl.. . . . . . .. ... . . _ . 3 700
Lakcwood.. ......._.. 3:325
LBko hvalon . . . . . . , . . . 3.200
3nrlsbad. . . . . , . . . . . . . 3,120
Dro Grande.. . . , . . . . . . 4 171
Loving. . . . . . . . . ., . , . , 4015
Zamon Seep. . . . . , . . . , 6,500
9.95
13.02
24
1910-1932
1907-1939
1RR7-1939
1893-1939
1916; 1919-1920; 1923-1939
1915-1920; 1925-1938
1909-191"
,II
ignfi: 19~.
I6-lRW
~..1908-1916; 1919-1939
1909-1928; 1930-1939
1909-1939
1905-1913; 1917-1926
1908-1939
1908-1932
1908-1926; 1933-1939
1913-1939
1911-1939
1909-3925
1909- 1939
1905-1906; 19121939
1909-1939
1913- 1939
1909-1939
1913- 1939
1909-1939
1908-1935; 1937-1939
1902-1905; 1916-1921; 1930-1939
1909-1939
1893; 1897: 1900-1939
1909-1927
1894-1939
1910-1932
1915-1918; 1920-1939
1919-1925; 1927: 1929-1939
1911-1916; 1918-1939
1911-1916: 1918-1939
1908-1910; 1914-1939
1903-1939
1895-1901: 1904-1909; 1922-1939
1910-1915: 1917-1925: 1927-1928: 19321939
1912-1924; 1928-1929; 1931-1939
1917-1939
1901-1925; 1927-1939
1905-1906; 1910-1939
1905-1906: 1016-1929
1906-1908; 1916; 1919-1938
1913-1929; 1932-1933; 1938-1939
1915-1025; 1927-1928; 1930: 1932--1939
1912-1925; 1927
1915-1939
1894-1899; 1901-1939
1905; 1910.-1939
1918-1939
1914-1939
1
Average of the maximum I
Averugc of the maximum I.
23
33
43
15
30
24
18
47
20
20
31
25
30
30
31
19
32
25
26
27
29
17
31
30
31
27
31
27
31
31
20
31
42
1.54
1.86
1.32
1.80
1.47
1.74
1.72
23
24
19
28
28
29
37
31
25
1.29
1.46
1.46
1.28
1.38
1.53
1.32
1.62
1.63
1.29
1.78
1.68
2.32
1.53
1.29
1.92
1.26
1.75
1.35
1.95
1.89
1.17
2.28
1.49
1.37
.95
1.60
1.01
1.65
2.07
1.58
1.66
1.40
1.61
1.96
1.81
1.77
2.18
1.49
2.05
1.69
1.84
1.84
1.75
1.37
1.57
1.75
1.42
1.68
1.61
1.58
1.72
1.95
1.35
1.99
1.97
2.47
1.70
1.36
a25
1.38
2.00
1.42
2.04
2.07
1.25
2.58
1.55
1.45
1.05
1.88
1.16
1.70
2.23
1.65
1.79
1.45
1.76
2.07
1.98
24
23
38
32
16
24
1.58
1.89
1.23
1.60
1.83
1.64
1.79
1.92
1.39
1.88
1.93
1.86
19
46
21
22
15
25
45
31
22
26
1.63
2.20
2.24
1.87
1.71
1.62
1.72
1.46
1.27
2.24
2.06
2.11
1.83
1.84
1.63
1.51
2.42
- r rain recorda
,rain record%
-
NEW
- --
-
-
-
-
-
--
4.20
3.85
2.28
L.70
i.40
t.35
1.69
IO1
1.43
125
283
i 10
2.60
3.45
5.70
6.50
2.51
4.15
3.22
3.95
3.65
3.08
3.55
2.70
3.80
4.80
3.03
2.88
3.31
4.05
3.75
3.20
4.21
3.92
4.90
4.50
3.50
5.80
2.60
5.65
4.18
4.20
4.60
2.49
7.20
2.47
3.28
2.01
5.50
3.04
3.13
6.98
3.00
3.78
4.13
3.15
5.10
4.78
5.60
4.55
2.59
3.44
3.30
4.30
3.72
3.05
3.80
2.70
3.06
5.40
2.35
3.00
3.40
4.30
3.85
3.50
4.25
3.50
5.01
5.10
3.80
6.35
2.71
6.20
4.70
4.50
5.00
2.65
8.00
2.51
3.48
2.13
5.60
3.25
3.34
7.70
3.18
4.08
4.65
3.20
5.55
5.10
6.40
7.22
2.60
4.45
3.35
4.30
3.93
3.23
3.85
2.74
4.05
5.50
3.20
3.00
3.59
4.45
3.92
3.50
4.60
4.30
5.04
5.10
3.82
6.58
2.73
6.40
4.70
4.50
5.00
2.65
8.01
2.51
3.50
2.13
6.20
3.35
3.34
8.00
3.20
4.08
4.65
3.25
5.60
5.20
5.35
L.80
2.70
1.62
1.43
1.70
4.00
3.15
1.20
1.75
3.20
6.40
2.40
4.67
3.38
3.89
4.20
2.21
6.00
2.40
2.90
1.81
4.50
2.60
2.82
5.70
2.72
3.45
3.40
2.95
4.40
4.20
5.00
L.25
2.45
3.26
3.16
3.90
3.50
2.98
3.45
2.65
2.92
4.60
2.27
2.88
3.10
4.00
3.65
3.20
3.90
3.28
4.83
4.50
3.40
5.60
2.58
5.50
4.18
4.20
4.60
2.45
7.10
2.47
8.20
2.00
4.90
2.90
3.13
6.70
3.00
3.78
4.13
3.05
5 05
4.62
3.50
3.20
2.81
4.00
3.01
3.8
5.0
4.0
5.0
3.2
4.1
3.1
2.9
5.3
3.91
3.42
3.2':
4.3i
3.1
4.5
5.7
4.4
5.4
3.5
4.6
3.5
3.1
6.1
4.00
3.42
3.35
4.75
3.21
4.5(
5.7.
4.4!
5.81
3.5.
4.8
3.51
3.2
6.2
4.30
3.55
3.65
4.0E
4.30
3.55
3.74
5.30
3.3(
5.0(
6.21
4.81
6.41
3.7
5.31
3.8:
3.51
6.81
4.50
2.25
2.38
1.52
3.00
1.89
2.48
3.90
2.37
3.00
2.65
2.45
3.50
3.25
3.60
4.29
2.13
3.18
2.75
2.91
2.79
2.55
2.61
2.45
3.00
2.82
2.50
2.40
2.50
2.90
3.20
2.25
3.12
2.90
4.15
2.90
2.40
3.85
2.14
3.61
2.59
3.40
3.60
1.91
4.70
2.25
2.49
1.60
350
2.09
2.49
4.30
2.40
3.00
2.65
2.65
3.6C
3.5c
3.80
3.65
2.16
2.85
2.75
3.12
2.91
2.75
2.74
2.50
2.60
3.15
2.03
2.56
2.45
3.22
3.16
2.55
3.13
2.80
4.30
3.35
2.60
4.05
2.21
3.88
3.04
3.60
3.81
2.05
5.20
2.32
2.62
1.68
3.55
2.18
2.69
4.67
2.56
3.16
3.05
2.65
3.95
3.68
4.20
4.95
2.26
3.45
2.91
3.21
3.05
2.75
2.90
2.54
3.28
3.37
2.68
2.56
2.75
3.22
3.40
2.55
3.49
3.20
4.40
3.35
2.72
4.40
2.30
4.20
3.04
3.60
3.81
2.10
5.43
2.32
2.73
1.73
4.05
2.38
2.69
5.10
2.60
3.16
3.05
2.82
4.05
3.90
2.88
2.90
2.12
2.7'
2.71
3.0
4.21
3.41
3.51
2.8
3.1
2.6
2.31
4.3
2.91
2.9[
2.2!
3.1'
2.7
3.0
4.3
3.4
4.1
2.8
3.4
2.6
2.4
4.4
3.20
3.08
2.45
3.16
2.81
3.4'
4.6,
3.71
4.0,
3.01
3.61
2.8'
2.51
4.8
3.28
3.10
2.58
3.64
2.98
3.4
4.7
3.7
4.6
3.1
3.8
2.8
2.6
4.9
2.70
3.25
1.90
2.66
2.36
2.45
2.33
2.25
2.10
2.18
2 50
2.06
2.18
2.12
2.10
2.30
2.80
1.81
2.58
2.40
3.50
2.20
1.90
3.00
1.83
2.75
1.92
2.79
2.80
1.65
3.65
2.00
2.06
1.37
2.63
1.62
2.15
3.23
2.OE
2.42
2.04
2.32
2.9C
2 8
3.30
3.31
2.00
2.67
2.50
2.82
2.66
2.55
2.41
2.39
2.42
2.62
1.91
2.40
2.19
2.90
2.91
2.25
2.81
2.60
4.00
2.90
2.29
3.49
2.04
3.30
2.51
3.40
3.60
2.41
2.5i
1.7L
2.5'
2.4
2.4
3.4
2.8
3.2
2.5
2.6
2.1
2.0
3.4
1.88
853
MEXICO AND ARIZONA
3.10
2.90
3 40
3 10
2.82
2.98
2.56
2.70
3.60
2.11
2.70
2.65
3.50
3.31
2.80
3.38
2.97
4.30
3.70
2.87
4.52
2.32
4.35
3.31
3.89
4.20
2.20
5.80
2.40
2.80
1.80
4.00
2.40
2.82
5.41
2.7E
3.42
3.4c
2.8C
4.3c
4.N
3.4t
3.21
2.7(
3.51
3.0
3.e
5.c
4.0
4.6
3.2
3.6
3.1
2.F
5.2
3.80
2.80
2.70
1.95
3.50
3.52
2.80
3.80
3.41
4.60
3.70
2.90
4.88
-
I
- - __ -
3.3
5.0
6.1
4.8
6.0
3.7
5.1
3.8
3.5
6.7
~
5.0C
3.8C
4.5c
6.4C
3.5
fi.0
7.0
5.4
7.5
4.1
6.2
4.4
4.1
8.0
149
150
151
152
153
154
155
156
157
158
159
160
161
162
3.11
3.75
2.70
4.08
3.90
4.68
3.73
5.25
5.85
4.30
7.25
2.89
7.20
5.42
4.78
5.35
2.85
9.10
2.58
3.78
2.28
6.50
3.68
3.55
9.00
3.38
4.35
5.30
3.40
6.20
5.60
4.70
3.69
4.15
5.78
3.4,
5.5
6.6
5.1
6.8
3.9
5.7
4.1
3.8
7.4
4.7(
3.6s
4 2
5.91
3.4
5.5
6.7
5.1
7.0
3.9
5.5
4.1
3 .8
7.4
5.00
3.80
4.50
6.40
3.51
6.01
7.01
5.41
7.51
4.11
6.2'
4.4
4.11
8.0
-
I
105
106
107
108
109
110
111
112
113
114
1 I5
116
117
118
119
120
121
122
123
124
125
126
127
128
139
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
7.00
5.00
2.79
3.76
3.50
5.00
4.20
3.20
4.80
2.70
3.30
7.20
2.50
3.20
4.00
5.00
4.20
4.20
5.00
3.90
5.40
6.40
4.60
8.00
3.00
8.00
6.00
5.00
5.60
3.00
10.00
2.59
2.45
-
8.00
9JJ0
2.79
5.00
3.52
5.00
4.45
3.50
4.50
2.80
4.46
7.20
3.48
3.20
4.04
5.30
4.20
4.20
5.30
4.90
5.40
6.40
4.60
8.00
3.00
8.00
6.00
5.00
5.60
3.CO
10.00
2.60
4.00
4.00
2.40 2.40
7.90
7.10
4.00 4.00
3.70
3.70
10.00 10.00
3.50 3.50
4.60 4.80
5.80 5.80
3.50 3.50
6.60 6.60
6.00
6.00
7.30
3.20
2.70
4.80
3.40
4.70
4.25
3.40
4.20
2.70
4.30
6.40
3.35
3.11
3.86
4.05
4.10
3.90
5.00
4.65
5.30
5.85
4.30
7.40
2.89
7.30
5.42
4.78
5.35
2.85
0.10
2.58
3.80
2.28
7.10
3.72
3.55
9.10
3.3Q
4.35
5.3c
3.40
6.2C
5.63
854
N I W M E X I C O AND ARIZONA
.
.
I
NO
.
Elevation
(feet)
Statloo
.
Average
annual
preeipi- Length
of
tation
through
1938
Cuchen)
TABLE 3.I
I
AvmRnom or
RBCORDUSBDFOR FRWW~PNC~
ARRAT
i-FAYzrn
EACH:
[;prd
Dates (inclusive)
(b) Am.
.
.
.
.
163 San Carlos ReYervoir ... 2. 532
12.12
50'
26
1.20
1.47
Thatcher .............
Clifton ...............
Benson ...............
San Simon ............
2.800
3. 465
3.523
3.609
9.55
13.43
11.07
7.68
39
50
58
48'
34
34
43
30
1.19
1.31
1.32
1.43
1.24
1.24
168 Bowie ................ 3.756
10.77
66
45
1.17
1.36
17
35
22
21
573
26
37
23
19
43
1.41
1.30
1.45
1.50
164
185
166
167
1.18
1.07
169
170
171
172
173
Fairbank .............
Douglas ...............
Lewis Sprinm .........
Allairea Ranch ........
Wdlcox...............
3.862
4. 184
4. 200
3. 939
4. 029
12.00
12.78
11.17
11.65
11.99
1.30
1.48
1.43
1.49
1.61
1.46
174
175
176
177
178
Coohise...............
Lealie Canyon ........
Naco .................
Tombstone ...........
Ft. Grant .............
4. 250
4.4G1
4. 579
4. 540
4.833
11.39
13.44
14.44
14.85
13.32
2 71
23
25
41
65
24
24
15
43
39
1.22
1.44
1.62
1.51
1.36
1.44
1.48
1.79
1.60
1.58
35
62
50
32
' 28
39
25
303
15'
27
26
40
19
45
47
24
1.44
1.36
1.79
1.43
1.73
1.21
1.69
1.14
1.35
1.30
1.38
1.12
1.28
1.43
1.46
1.75
1.67
1.99
1.87
6.484
6.500
6.500
6 862
G:925
7.054
8.500
16.Q6
18.45
19.98
18.73
21.38
12.98
18.53
17.64
18.94
18.89
19.07
11.79
23.11
22.91
23.28
194 Greer ................ 8.500
22.18
223
18
1.23
1.42
980
195 Buckeye ..............
196 Phoenix W .B......... 1.108
107 Marinette ............. 1.150
7.80
7.78
7.82
50
62
253
48
44
1.03
1.10
97
1.37
1.27
1.40
.
179 F t Huaehuca .........
180 Ft Apache ............
.
181 Bwty ................
182
183
184
185
186
187
188
189
190
191
192
193
Paradwe ..............
Rucker Canyon ........
Snowflake.............
Portal ................
Show Low ............
Heber ................
Blue .................
Pinedale ..............
Springerville..........
Henrys Camp .........
Lakeside ..............
Alpine ................
I
18
33
20
17
13
15
29
30
23
21
25
23
203
29s
24
.
1.89
1.27
1.86
1.63
1.98
1.59
1.68
1.17
1.67
1.93.
1.76
Tempe Data Orchard ..
Litohfield Park ........
Marieopa .............
Ooirlde Ranch .........
Goodyear .............
Chandler .............
MwaExperiimentalFarm
Sacaton ..............
Granite Reef Dam ....
C w a Grande ..........
1.165
1.180
1.186
1 195
1:203
1.213
I. 245
1.280
1.325
38
21
84
24
14
22
44
31
46
503
36
22
43
26
15
21
43
33
46
36
1.04
1.17
1.26
97
1.01
1.10
1.02
1.400
8.74
8.22
8.12
7.41
7.78
8.16
8.69
9.60
9.52
8.30
.97
1.14
1.33
1.45
1.41
1.35
1.24
1.38
1.26
1.44
1.31
1.36
208 Cam Grande Ruin .....
209 Florence ..............
1.422
1.500
9.73
9.88
233
38'
15
28
1.25
1.18
1.62
1.37
210 Morman Plats.........
211 Redrock ..............
212 Canon ................
213 Dudleyville ...........
214 Intake . . . . . . . . . . . . . .
216 Roosevelt .............
216 Gisela ................
1.815
1.856
1.990
2.204
2. 230
2.275
13.54
9.61
17.92
14.60
13.41
17.86
143
35'
153
37
33
34
14
29
12
30
34
35
1.64
1.17
1.57
1.34
1.29
1.09
1.87
1.38
2.34
1.56
1.65
1.60
1.57
198
199
200
201
202
203
204
205
206
207
.
2.300
18.78
20
273
.
1.28
1.19
-
* Average of the maximum l-day rain recorded for the
* Av0rage of the maximum l-day rain reoorded in each
8
Some missing months interpolated from surrounding
855
N E W MEXICO AND ARIZONA
- - .88
.21
.40
- 1.49
1.09
- -
- -
-
-
.19
1.37
3.41
3.70
3.72
1.91
3.91
163
1.55
1.08
1.42
1.40
2.57
2.08
2.47
3.55
1.70
1.09
1.58
1.61
2 70
2 09
2.60
1.00
!.79
!.09
!.70
1.75
2.80
1.10
1.70
1.35
t64
t65
166
167
1.45
1.88
.2R
.01
.12
.63
1.30
l.22
.45
.05
.33
.I6
1.15
1.98
.58
.BO
.81
-
1.25
8.00
2.09
1.00
1.00
.D3
.88
1.08
.98
1.70
-
2.15
1.98
2.03
2.38
.92
.82
.71
.75
81
2.G5
- -
1.08
!.05
,713
.79
!.OO
1.90
2.07
1.92
1.18
1.05
1.24
2.00
2.30
2.16
2.36
8.17
2.40
168
!.lo
1.84
1.84
1.18
1.00
.48
.09
20
.42
.10
!.49
!.28
!.25
!.4U
1.44
2.62
2.35
2.46
2.60
2.40
2.62
2.54
2.51
2.63
2.69
1 70
2.5R
2.68
2.70
1.60
1.70
!.72
!.71
1.72
!.SO
1.82
3.00
3.08
1.90
3.04
1.82
1.15
,.12
1.91
1.25
2.90
i.30
3.36
1.01
3.35
2.90
3.40
3.41
3.01
3.50
1.95
1.69
3.70
1.16
1.72
2.95
3.75
3.78
3.15
3.79
1.00
1.00
1.98
3.00
LOO
1.01
$.a2
1.00
LOO
169
170
171
172
173
1.93
1.00
1.49
1.15
1.13
1.18
1.40
1.91
1.31
1.40
1.29
1.40
1.02
1.50
1.45
2.35
2.62
3.25
2.50
2.60
2.45
2.62
3.34
2.68
2.63
2.50
2 80
3.49
2.61
2.75
!.58
!.80
1.12
:.01
!.98
1.00
2.00
3.39
1.30
3.00
3.20
2.95
3.39
4.30
3.10
3.20
3.08
3.59
1.68
3.18
3.40
3.10
3 59
4.08
3.21
3.40
LZO
3.20
1.68
!.79
!.79
2.73
3.12
3.97
2.85
3.00
1.16
2 15
a.55
2.40
2.27
1 GO
2.26
2.06
2.60
2 14
.92
2.00
2.49
3.16
2.48
2.25
2 06
1.92
2 48
2.65
2.5%
!.60
1.94
1.67
1.51
1.75
1.31
l.G4
1.51
j.50
l.59
l.59
1.92
3.35
3.10
2.64
2.10
3.11
3.91
2.75
2.71
2.62
2.45
1.90
2.70
2.38
2.22
2.12
2.85
3.07
2.75
!.72
1.29
t.15
1.00
!.9t
1.65
l.70
1.70
1.69
1.70
l.73
l.12
$95
1.46
1.79
2.18
P.40
1.30
2.15
2.28
1.65
2.34
2.18
1.97
1.82
2.28
2.45
2.40
2.50
2.75
3.40
3.30
2.65
2.15
2.69
2.43
3.36
2.50
2.50
1.84
3.08
3.04
2.58
2.02
2.70
3 40
2.58
2.58
2.30
2.34
1.72
2.81
2.85
2.50
2.00
2.89
2.48
2.30
2.28
3.12
3.37
2.86
2.81
3.50
4.50
4.33
3.00
2.89
2.85
2.80
3.80
2.79
2 81
2.28
4.35
3.65
2.89
1.18
3.77
1.70
2.98
2.92
3.10
2.60
2.11
3.06
2.52
2.43
2.40
3.43
3.70
2.95
2.90
3.81
4.00
4.74
3.14
3.15
2.95
2.90
3.94
2.83
2.92
1.46
2.18
2.38
2.18
!.82
!.32
!.35
1.95
!.20
..52
!.18
!.06
I.86
1.69
2.02
1.20
1.18
1.39
l.52
3.10
3.00
1.50
1.05
2.48
1.30
3.18
1.39
2.35
1.70
2.71
2.80
2.45
4.85
3.85
2.95
1.20
1.00
LOO
3.05
3.00
3.30
2.65
2.20
3.20
2.60
a.50
2.60
3.65
4.00
3.00
1.84
1.87
2.K
1.97
2.25
2.05
2.32
2.19
1.49
2.28
2.59
2.35
2.69
2.40
2.74
194
4.00
3.20
4.90
4.00
3.20
5.00
195
196
197
3.50
3.00
3.70
2.50
3.00
3.60
3.50
198
199
200
201
202
2 04
1.21
2.48
2.48
!.SO
2.87
2.40
1.22
1.79
5.00
3.30
1.65
3.79
6.00
3.30
3.55
174
175
176
177
178
2.98
4.00
5.20
5.00
3.20
a.30
a.oo
3.00
4.00
2.90
3.00
2.50
5.20
4.00
3.00
1.79
1.78
1.95
2.15
2.16
2.10
2.2c
2.H
2.5(
2.48
2.40
2.46
2.49
2.4c
2.84
2.70
2.50
2.7G
2.70
2.50
3.10
3.09
2.80
3.40
3.09
2.80
3.69
3.4c
3.0(
3.8:
3.40
3.00
4.10
3.75
3.08
4.45
3.75
3.08
4.60
1.66
2.22
2.06
1.90
1.77
2.01
2.61
2.6<
2.1:
2.2:
2.76
2.9E
2.21
2.2c
2.45
2.2:
2.3s
2.11
2.9(
2.35
2.66
3 10
2 30
2.31
2.55
2.30
2.44
2.01
3.11
2.99
2.iQ
2.3s
4.7c
3.29
2.98
3.62
2.48
2.85
3.31
3 25
2.90
2.09
5.40
3.29
2.98
3.65
2.48
2.85
3.33
3.28
2.9c
2.45
5.4c
3.50
2.31
4.1C
3 O(
2.9(
3.5(
2.11
2.7(
3.0:
2.9
2.71
2.01
4.51
3.00
2.95
3.52
2.45
2.70
2.M
2.2(
3.3[
2.72
2.61
3.39
3.40
2.54
2.86
2.67
2.65
2.05
3.95
2.76
2.91
3.40
2.40
2.54
2.93
2.74
2.0'
2.5'
2.17
2.56
2.95
2.21
2.17
2.39
2.08
2.33
1.95
2.73
2.4c
2.82
2.01
1.87
1.87
1.91
2.39
2.62
2.02
1.99
2.15
1.85
2.18
1.9c
2.3C
1.90
1.76
2.21.
1.92
2.31
1.9:
2.6C
1.9E
2.61
1.98
2.81
2.00
2.9(
2.0(
3.35
2.05
3.4C
2.06
3.71
2.01
8.8C
2.06
4.18
2.08
4.21
4.60
2.09
4.50
2.0g
208
209
2.61
1.89
3.40
2 02
2.13
2.81
1.9f
2.N
2.2:
2.21
1.7(
1.8
3.21
2.01
4.01
2.31
2.5'
3.18
2.0:
3.1(
2.3f
2.3f
1.8:
1.91
3.51
2 1:
4.2:
2.4'
2.7:
2.4.
2.1:
3.41
2.06
3.21
2.4s
2.4c
1.91
2.OE
3.7(
2.11
4.51
2.5:
2.8:
3.91
2.18
3.45
2.66
2.6E
2.OC
2.2c
4.1:
2.21
4.75
2.7(
3.11
4.2'
2.2
a.61
2.78
2.61
2.1
2.3'
4.46
4.68
e 28
3.71
2.00
2.92
2.28
2.41
4.71
2.21
5%
2.9(
5.00
a.30
3.80
3.00
3.00
2.32
2.49
6.0C
a.3~
6.4(
3.0(
3.H
3.0(
2.N
210
211
212
1.92
1.62
2.04
1.8E
2.01
2.2!
2.0(
2.2;
2.31
2.0
3.11
2.3c
2.31
2.6:
a.ar
2.5;
2.21
- eaoh year of record.
2.6E
2.7(
2.31
3.11
2.21
6.N
2.N
3.21
2.M
2.31
-
2.08
3.1(
2.9:
2.41
a.oo
3.70
2.50
a.oo
a.60
3.50
3.00
2.10
6.00
3.00
2.50
6.00
- -
a13
214
215
216
856
NEW MEXICO AND ARIZONA
TABLE 3.-
No
.
Elevation
(feet)
Statlon
I
.
CORD
u8gD FOR
l-FAyz&
EACJJ:
FRBQWNCI ARRAY
E;$):
.
I
I
AvlDBhOl OF
Average
annual
praoipl- Le:fth
tation
through
1938
(Inches)
I
Dates Ouclndve)
. .
I
(b) ARIZONA-
.
.
Tucson Univ of A h ..
Childs (Verde
Hot Springs)
Superior ..............
Alnmo Ranger Station ..
Vnil ..................
Globe ................
2.423
11.28
72
1915-1940
26
1.32
1.46
2.650
2.990
3. 155
3.241
3.440
16.93
18.63
13.88
9.07
16.17
24
19
1915-1940
i92n-1940
1899.1910 . 1912-1915
1916-1040
26
21
25
16
37
1.38
1.52
1.34
1.08
1.29
3.17
1.81
3.465
11.31
17.79
19.82
13.19
12.89
17.19
18.411
17
45
27
14
15
32
14
1.21
1.51
1.47
1.32
1.04
1.51
1.43
19.28
17
49
25
15
14
33
158
22
4. 000
4.044
4.300
4. 400
21.89
17.85
19.70
21.75
205
18
245
29
20
19
24
18
1.62
1.46
1.69
1.46
235
236
Pinal Ranch .......... 4.530
4.522
25.57
19.72
46
465
46
43
1.65
1.44
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
Tonto Ranger Station ..
Rosmont .............
Yeager Canyon ........
Elgin .................
Payson ...............
Natural Bridge ........
4.732
4. 800
4. 850
4.900
4.906
4.607
5.225
5.250
5.354
6.000
141
350
492
538
685
737
871
1.652
1.770
1.775
2 .072
3. 688
4.782
4.150
4. 900
16.36
17.73
18.10
15 85
21.04
25.50
19.82
19.12
20.52
28.09
3.47
6.16
4.81
4.12
4.57
5.88
6.19
7.33
9.16
8.22
9.55
13.55
19.10
7.07
6.29
24
17
22
27
40’
49
28
42
73
24
69
46
23
56
213
453
24
183
26
30
385
14
25’
12
44
23
13
23
28
35
48
30
43
25
25
43
45
23
41
20
39
27
13
27
32
32
1.53
1.42
1.45
1.62
1.56
1.62
1.89
1.32
1.31
15
35
.69
262
263
264
Winslow ............. 4. M8
Holbrook ............. 5.069
St Johns ............. 5. 650
8.60
9.25
12.17
266
266
267
268
269
2711
Pinto .................
b e n t s ..............
Chin Lee .............
Ft . Defiance ..........
8t Mlohaels ..........
Ft MohaPe ...........
5. 660
5.800
6.090
6.950
6. 950
640
I
3. 142
217
218
219
220
221
222
223
224
225
226
227
228
229
230
23 1
232
233
234
........
.......
Clemenceau
Walnut Grove .....
Miami. ...............
Silverbell
Cordes .........
Nogales ..............
Fieanal Ranch .........
Santa Marpuerita ......
Sycamore Ranger
Station .............
Pataganis .............
Helvetia ..............
Young ................
.......
CanUte ...............
Jerome ...............
Preacott ..............
Crown King ...........
S i p 1................
AJO..................
Salome ...............
Wickenhurg .......
Congress..........
YarneU ...............
Leupp ................
Tuba City ............
3.469
3.603
3.604
3.773
3.839
4.000
4.000
.
..
271 Lee’s Ferry ...........
.
6
.
.
.
2Pa
143
20
1894; 1901-1902; 1905; 1907-1928; 1930-
24
1.82
1.96
.90
...80
68
83
.on
.81
.95
14
.83
1.12
1.01
1.25
1.22
18
1.50
40
42
393
30
44
35
1.00
.97
1.06
11.83
8.80
8.75
13.68
13.15
5.09
19
26
25
30
22
58
18
24
22
20
20
26
1.06
.82
.92
.94
1.12
6.20
22
20
.73
.75
.81
.
1 Average of the maximum 1-1
Average of the maximum I d
%Somemissinn montlla iiiterii
1
rain reoordl
rain recorde
ted from SUI
1.48
1.26
1.50
857
1.85
1.73
2.19
1.92
1.75
1.61
I
1.78
2.02
1.91
2.00
1.61
1.81
1.88
2.48
2.55
1.88
2.28
2.11
I
2.12
1.30
2.57
2.38
2.03
1.97
1.98
!.38
!.61
1.30
!.lo
1.90
1.93
2.96
2.25
2.05
2.35
2.03
2.10
2.60
1.68
2.58
1.28
2.19
2.28
2.30
1.99
.75
.03
A0
.7 1
I
3.08
2.29
2.60
2.51 ,
1.10
1.50
2.69
2.30
2.11
1.89
1.96
2.11
2.18
2.08
!.76
!A0
!.55
!.11
i.70
1.90
2.63
2.22
2.35
2.50
2.58
2.72
1.83
1.70
2.60
1.30
1.05
.96
1.27
1.43
1.17
1.35
1.06
1.53
1.47
1.87
2.02
2.00
.98
1.05
3.30
2.72
2.37
2.31
2.28
3.20
2.28
1.98
2.50
1 2.51
3.12
1.60
1.41
1.87
1.70
1.57
1.60
1.62
1.56
1.5?
1.45
1.65
1.61
2.1(
2.0!
2.0:
2.61
2.8'
1.0:
1.1!
2.50
I
2.50
2.28
2.08
2.72
3.76
1.95
2.55
1.48
2.41
2.6s
I
3.19
3.00
2.61
2.38
2.21
2.85
1.20
1.to
1.66
1.52
2.51
2.81
3.70
2.60
2.20
3.00
2.50
2.26
3.30
3.35
2.95
2.48
2.25
2.72
2.55
2.03
3.83
3.50
4.23
2.81
2.26
3.44
2.79
2.31
3.75
3.90
3.20
2.61
2.30
3.10
2.71
2.07
4.00
1.08
.15
.45
.63
.05
3.30
2.55
2.75
2.70
1.34
2.70
1.75
3.19
3.42
2.71
2.81
2.82
3.45
2.89
2.82
3.25
8.80
2.90
,BO 2.43
1.18
1.95
1.00
!.55
1.41
1.51
1.23
.93
.43
.55
.70
.80
.19
t.27
3.31
3.40
3.28
3.23
2.78
3.88
3.9(
3.04
2.51
.I5
.60
.70
.82
.99
.56
1.60
2.99
2.30
3.79
3.00
2.36
4.10
4.60
3.55
-
-
00
:.lo
00
35
87
49
.40
i.00
1.40
t.90
t.01
1.70
3.20
4.64
3.56
3.00
2.57
2.6B
6.50
6.00
3.45
2.40
4.9a
3.80
2.45
5.40
7.85
4.61
3.35
2.46
5.40
3.59
2.19
5.95
.90
.75
.15
38
3.90
3.77
3.15
3.45
1.00
1.00
3.20
3.50
#.20
8.50
.oo
.oo
131
!32
!33
!34
,.65
:.91
G.35
4.70
3.80
3.00
1.80
1.00
!35
4.50
3.50
3.50
3.5c
1.50
1.00
1.50
LOO
LBO
3.20
5.70
137
138
139
240
241
242
243
.so
.20
3.8C
3.5(
3.06
3.4(
5.30
4.00
;.'lo
1.80
5.7:
4.3
1.30
!.70
3.57
3.50
3.40
2.9G
4.22
4.2(
1.59
!.90
1.00
1.08
3.32
4.33
4.40
.50
3.M
.I30
3.01
31
.01
.54
1.45
!.32
1.33
t.70
1.80
2.51
1.23
1.60
3.2(
4 1(
7.2(
2.8:
2.3
2.0:
2.2:
2.3
1.91
2.8'
1.9
2.9
2.71
2.7
3.0
3.5
1.2
1.7
1.46
1.12
5.80
3.32
2.38
1.31
2.18
2.72
1.58
3.3c
1.56
2.85
2.6:
2.95
2%
2.7(
13
1.8'
3.88
4.00
3.80
3.30
4.95
4.8C
4.4E
3.5c
4.6E
8.N
3.4i
2.7:
2.14
2.5(
2.7:
2.0:
3.41
2.0:
3.2:
2.91
.30
.40
.08
1.89
1.10
1.20
1.21
1.55
1.91
L.80
217
'.OO
8.00
8.50
3.G6
3.25
2.98
3.36
.57
32
.16
I
7.90
6.70
3.65
2.45
5.50
4.19
2.47
6.00
.66
.12
.95
.O 6
.40
00
00
30
.70
5.42
3.80
3.18
2 05
2.86
5.00
3.60
3.05
2.G5
2.80
.12
.74
.94
.OB
60
.oo
.oo
6.40
3.82
3.20
2.68
2.91
.40
.I5
.ll
.38
I
3.80
3.43
5.40
5.40
3.25
2.38
4.45
3.48
2.41
4.85
30
.75
.92
I
3.43
3.25
.11
31
.01
.5!
.51
,.2
.si
#.71
3.01
3.0,
3.7
1.3
2.0
3.53
3.20
5.40
3.83
2.70
1.34
2.30
3.00
1.61
3.81
1.67
2.9:
2.86
3.K
2.9:
2.N
1.34
2.0(
23
1.32
:.40
1.40
1.80
i.62
i.30
1.62
.31
.58
30
.81
.15
.75
35
8.89
t.50
1.01
.51
1.30
1.26
!.87
1.28
L.24
1.50
1.09
1.65
1.16
3.43
3.09
3.95
1.38
2.40
.30
.70
.oo
!.50
1.00
1.80
!.20
1.40
4.0C
6.2(
5.H
2.M
2.3
8.0(
5.0(
3.4!
1.4(
2.51
3.51
1.71
5.01
1.81
3.51
3.2'
3.5
3.0
3.0
1.4
2.3
.oo
.oo
.10
.so
.50
.oo
.45
.50
.50
4.00
!18
!19
!20
!21
122
!23
224
125
126
227
228
229
230
!36
244
a.ii
1.88
3.49
1.92
1.46
1.12
1.68
1.90
1.37
1.90
1.28
1.71
1.91
2.30
2.60
2.29
1.15
1.32
1.85
3.48
5.98
2.18
1.9s
1.88
1.91
1.91
1.71
2.21
1.81
2.5:
2.41
2.35
2.8!
3.21
1.11
1.41
'25
.96
.05
1.32
.72
..20
..86
1.15
1.45
1.28
1.38
1.14
1.18
2.53
1.75
2.41
1.20
1.49
3.0f
3.8:
6.6!
2.5:
2.21
1.91
2.11
2.1!
1.8
2.5'
1.9
2.7
2.6
2.5
2.9
3.4
1.2
1.6
2.:
1.25
7.35
4.49
3.12
1.37
2.42
3.28
1.67
4.50
1.73
3.2f
3.06
3.4(
2.9s
2.91
1.36
2.1(
1.95
1.83
1.80
2.0
1.9
1.8
2.09
1.99
1.95
2.15
2.05
2.00
2.41
2.31
2.2:
2.4
2.3
2.2
2.61
2.5
2.4:
2.1
2.:
2.1
2.8!
2.71
2.6!
2.86
2.82
2.61
3.00
2.98
2.80
3.00
3.00
2.80
262
263
264
3.15
2.47
1.72
1.80
2.21
1.01
1.8
1.41
1.6
2.1
2.4
2.9
1.8
2.4!
1.6
1.8'
1.4'
1.6
2.2
2.1
3.:
l.!
2.1
2.
2.
2.7!
1.6.
1.91
1.4'
1.7
2.2
2.8:
3.6:
1.N
2.1:
2.8!
2.41
2.97
1.66
2.00
1.50
1.71
2.29
3.0C
2.01
2.2(
3.0(
2.51
265
266
267
268
289
270
2.4
2.
2.7
2.8
3.01
271
.62
.91
.25
.99
!.31
,.50
!.GO
1.38
1.31
1.33
1.41
1.41
1.4'
1.73
1.65
1.63
1.8
1.7
1.71
1.34
1.30
1.29
1.16
1.45
1.32
1.5
1.5
1.2
1.4
1.6
1.6
1.61
1.51
1.52
1.26
1.55
1.90
1.8
1.9:
1.5.
1.6
1.9
1.9
i.nc
1.5:
1.6;
1.31
1.5;
2.0!
2.0
2.2
l.f
1.7
2.1
2.1
1.94
1.58
1.7C
1.34
1.61
2.N
1.03
1.2
1.39
1.6
1.61
1.1
1.78
~
I
-
L
-
I 1.98
cord.
each year
pmiid June 1-Septa er 3
year of reoord.
for computation of average annual precipitation.
2.1
80
.
1.2
:.9
1.0
1.2
!.6
1.0
1.1
3.9
!.O
3.4
3.0
3.2
3.C
3.6
1.:
-
3.00
_
.
245
246
247
3.51 248
2.30 249
3.00 250
3.50 251
2.30 252
5.00 253
2.10 254
3.80 255
3.25 256
3.60 257
3.10 258
4.00 259
1.41 260
2.54 261
5.80
0.80
5.00
4.0(
-
858
N E W MEXICO AND ARIZONA
Average
NO.
Elevation
(feet)
Station
AvERAaa OF
annual Le:fth
precipltation
through record
1938
(years)
l-k:'","N
EACE:
RECOEDUSEDFOR FREQUENCY
ARRAY
(Inched
Dates (Inclusive)
(b) ARIZONA-
-
-
272 Supal . . . . . . . . . .. . . . . , 3,200
..
273 Kingman. . . . . . . . . . . 3,326
274 Truxton.. . . . . . .. .. .. , 3,997
Cedar Glade. . . . . . . . . .
Pmoott Dry Farm. . . .
Walnut Creek Ranner
Station.. . .. . . . . . . . .
Ashfork.. . . . . . . . . .. . .
275
276
277
278
Selipman. . . . . , . . . . . . .
Williams.. . . . ... . . .. ..
Grand Canyon. . . . . . . .
Flagstaff.. .. . . . . . . . . ..
Ft. Valley. . . . . . . . .. . .
279
280
281
282
283
-
4,610
5.008
14.30
14.34
1 Tt
5,138
5,160
1914-1915; 1917-1918; 1921-1922; 19241927; 1930-1932
1901-1902; 1904-1940
1910-1917; 1921-1022; 1924-1925; 1927lOAn
I19i5-;940
1913-1928
1916-1910
19~,9;~910;1912-1913; 1915-1928; 1930-
13
39
1.17
39
26
1.13
1.24
1.74
1.46
26
16
1.28
1.47
1.68
1.59
25
29
1.42
1.20
1.95
1.44
33
35
36
45
17
1.14
1.39
1.10
1.20
1.25
1.37
1.97
1.38
1.82
1.73
lUY"
6,219
6,750
6,866
6 907
7:500
11.04
22.32
17.22
22.80
24.33
343
43
38
51
30
1905-1909; 1012-1935; 1937-1940
1904-1905; 1908-1940
1904; 1906-1940
1894; 1897-1940
1914-1924; 1935-1940
I
Average of the maximum 1-day rain recordei ir the
Averare of the maximum I-day rain recorded each
a Some missing months interpolated from surrounding
1
2
given year, in which case i t was necessary to decide whether to include the year.
The decision was made after inspection of the complete record t o determine
what quantity constituted a high rainfall at that station. Depending on the
number and season of the missing months, the year was included in the array
if i t appeared probable t h a t the available record included the day of highest
rainfall for the year.
If the data do not plat as a straight line in the recurrence-interval curve,
the relatively few widely-spaced points in the upper limits of the series determine how the curve will be drawn and will control the extrapolation. I n this
study two curves (summer and all-year) were drawn for each of 283 stations.
They represent stations in all kinds of topography in regions of average annual
precipitation varying from 8 to 30 in. By far the most important factor
affecting the extrapolation of the curves was neither the manner of choosing
the series, nor the length of record, but the occurrence of aberrant points in
the upper limits of the series. When such an aberrancy occurred the position
of the curve was mostly a matter of judgment.
I n the Southwestern States there is great variability in both the average
annual precipitation and in the magnitude of the highest one-day rainfalls
that occur in successive years. One year may include a number of heavy
rainfalls and may have a high total precipitation] whereas tho following year
may be dry, with no high rains. To demonstrate this variability t h e heaviest
rain of record each year was used in the present analysis. The recurrenceinterval array, therefore, is comparable to the method used by the late Allen
Hazen,6 M. Ani. Soc. C. E., in which he computed from stream-flow records
0
"Flood Flows," by Allen H:i7en, John Wdey and Sons. New Yorh, N. Y . . 1930
859
N E W M E X I C O A N D ARIZONA
_.
- --
-
2.60
1.82
2.90
1.93
3.11
2.14
3.47
2.29
3.68
2.40
3.86
2.50
4.00
272
3.10
2.82
2.61
2.90
3.40
3.18
2.71
3.20
331
3.41
2.89
3.75
4.05
3.95
2.95
4.20
4.3 1
4.30
2.99
4.65
4.65
4.72
3.00
5.00
4.90
5.00
273
2 74
2.61
2.23
2.16
2.33
2.68
2.35
2.20
2.41
2.78
2.41
2.28
2.55
2.93
2.55
2.30
2.Gl
3.00
2.G3
2.32
2.71
3.10
2.71
2.32
2.75
3.20
2.75
275
27G
3.05
1.98
3.05
2.00
3.46
2.07
3.40
2.04
3.79
2.14
4.20
2.12
4.46
2.28
4.75
2.18
5.00
2.35
5.50
2.21
5.55
2.42
6.00
2.22
6.00
2.50
277
278
2.17
3.10
2.00
2.24
2.39
2.00
2.04
2.00
1.85
1.90
2.30
3.33
2.17
2.40
2.57
2.09
2.10
2.15
1.91
2.00
2.41
3.51
2.30
2.51
2.70
2.24
2.20
2.42
2.06
2.16
2.62
3.86
2.53
2.75
3.00
2.31
2.27
2.60
2.18
2.28
2.75
4.10
2.70
2.90
3.18
2.41
2.31
2.83
2.27
2.39
2.90
4.33
2.88
3.08
3.38
2.48
2.35
3.00
2.32
2.48
3.00
4.50
3.00
3.19
3.50
279
280
281
282
283
-
period June 1-Septen er 30 in each year of
-
~
-__
cord
stations for computation of average annual precipitation.
the highest peak discharge each year of record, the average of which he termed
“average annual flood.” I n Table 3, the data on the average of highest rainfall each summer and of highest rainfall each year are comparable t o Mr.
Hazen’s “average annual flood.”
ISOPLUVIAL
MAPS
The isopluvial maps published by Mr. Yarnell2 were based on five stations
in the Southwestern States. I n spite of the fact that the present analysis
includes frequency curves for 283 stations in the same region, due to marked
variation in frequency curves for closely adjacent stations of comparable
records, isopluvial maps are difficult to construct. This difficulty can be
attributed to a number of facts. Owing to the great divergence in topographic
relief between closely adjacent points, two stations within a very short distance
of one another may be in very different topographic settings. One may be in
the middle of a broad, flat plain, the other in a deep, narrow mountain canyon.
It appears from the present analysis that stations above El. 7500 experience
relatively few high rainfalls. This indicates that elevation above sea level
has some effect on the frequency characteristics, although ruggedness of relief
and position of the station in relation to the source of moisture and the surrounding mountainous areas probably are of more direct importance.
The small areal extent of high rainfalls occurring in summer-type storms is
a factor leading to differences between stations since any high-intensity,
individual storm rarely is recorded a t more than one station.
The 24-hr rainfall quantity expected t o be equaled or exceeded once in 50
years a t various stations in relation to topography is shown by the relief maps
860
NEW MEXICO AND ARIZONA
N E W MEXICO AND ARIZONA
86 1
862
NEW MEXICO AND ARIZONA
NEW MEXICO AND ARIZONA
863
864
NEW MEXICO AND ARIZONA
of Figs. 3 and 4. These maps demonstrate the variability of the recurrenceinterval figure between closely adjacent stations, and they indicate the position
of the stations relative to the major mountain masses. Stations in deep
mountain valleys, for the most part, are shielded from the effect of moisturebearing air masses moving into the area and tend to have low rainfall expectancy. This is not true in all cases, but the relief apparently offers sufficient
explanation for the relative magnitude of the recurrence-interval figure for
certain stations. I n other cases, two stations in apparently similar topographic
positions have quite different expectancies.
I n spite of these differences between individual stations, certain general
patterns of rainfall expectancies are apparent in New Mexico and Arizona.
The area in southeastern New Mexico, particularly along the eastern flanks
of the Delaware, Sacramento, and Capitan mountains, is subject to high
rainfalls because summer moisture moving in from the south or southwest
impinges on these topographic barriers. The same is true for northeastern
New Mexico: I n the central Pecos watershed no important topographic barrier
obstructs the moisture-bearing winds south of the relatively rugged country in
the headwaters of the Pecos and Canadian rivers.
The Black Range between Silver City and Hillsboro in southwestern New
Mexico forms a barrier to south winds and protects northwestern New Mexico
from high rainfalls. Stations in the Rio Grande Valley as far north as Albuquerque, N. Mex., however, are subject to high rains from moisture moving
up the valley.
I n Arizona, the mountainous area of the central and northwestern portion,
particularly along the Mogollon and Yarnell escarpments, is subject to high
rainfalls and tends to protect or shadow the northeastern plateau country.
These relationships can be easily visualized by inspection of Figs. 3 and 4.
From these generalized relations an isopluvial map for 50-yr frequency has
been drawn and is presented in Fig. 5 . No attempt was made in the preparation of this map to draw each "isopluve" in the exact position indicated by the
computed value for each individual station, but the lines were generalized to
indicate broadly the comparative expectancies of various regions.
I n the use of the recurrence-interval data presented herewith, engineers
are cautioned to compare the topography and position of the point for which a
recurrence-interval value is desired with those factors affecting all stations
near the particular point. Moreover, it must be remembered t h a t the data
presented are for a 24-hr period, but in the summer type of rainfalls, the
maximum rainfall in 24 hr probably fell in a much shorter period of time.
The value of total storm rainfall for a given recurrence-interval in the summer
period may be used in connection with average intensity-time patterns for the
purpose of designing engineering structures.
APPLICABILITY
OF STATION-YEAR
ANALYSIS
One method of ironing out differences between recurrence-interval curves
of adjacent stations and improving the value of short records is a combination
of stations by the station-year method. The requirements for use of this
NEW MEXICO AND ARIZONA
865
method discussed by H. C. S. Thorn‘ and Katharine Clarke-Hafstade may be
summarized as follows:
f
(1) Stations grouped must be mutually independent-that is, far enough
apart so that no single storm covers more than one of the stations; and
(2) Stations grouped must be included in a meterologically homogeneous
region.
FIQ.(I.-ISOPLUVIAL
MAP O F ARIZONAA N D Nmw M X U C O (24-HR RAIN EQVALSD
OR EXCEHlDBD O N C l I N 50 YmAR8)
Mr. Thorn defines a meteorologically homogeneous region as an area each
point of which would have identical frequency curves of rainfall. He states
that delineation of such a region by this criterion is impractical since “assignable
causes,” such as topographic differences, operate to produce dissimilarity of
rainfall experience at various points within the region; and he suggests, therefore, that homogeneity must be established by meteorological studies. Assignable causes operate in the following way: A storm situation, one favorable for
rain, prevailing over a region may be so weak t h a t rainfall occurs only at
points that are subject to significant orographic effects, and these stations,
over a long period, would therefore experience more rainy days than do stations
with assignable causes of lesser magnitude.
Although i t is possible, in New Mexico and Arizona, to delineate meteorologically homogeneous areas defined by meteorologic studies, recurrenceinterval curves at various stations within such a region may be so different
that assignable causes appear to operate in these states to such a n extent that
there may be more difference between curves of stations within the homogeneous area than between two stations in dissimilar meteorologic regions.
-
7 “On t p e Statistical Analysin of Rainfall Data,” by Herbert C. 8. Thorn, Tmneaetiona, Am. Geophysical Uxuon, Pt. 11, 1940, pp. 490-498.
8 “Reliability of the Station-Year Rainfall-Frequency Determinations,” by Katharine Clarke-Hafstad.
Tranaaclions, Am. Soa. C. E.. Vol. 107 (1942), p. 633.
866
.
NEW MEXICO AND ARIZONA
Examples of station-year groupings were platted in connection with the
present'study. It did not appear satisfactory to group stations by the stationyear method, although the stations were in meteorologically similar regions,
inasmuch as the frequency curves were so distinctly different.
RAINS
I n the use of frequency-magnitude data for design, it usually is necessary
to apply an intensity pattern to a given rainfall total. I n general, i t may be
stated that in New Mexico and Arizona summer rainfall depths published as
24-hr totals characteristically fall in a period much less than 24 hr-usually
less than 10 hr. Since design storms ordinarily are assigned an intensity
pattern that would result in relatively high stream discharge, the rainfall
magnitudes for summer listed in Table 3 logically may be used with the
characteristic intensity patterns presented in Fig. l(a).
The great winter floods in these states are the result of rainfalls extending
over a period of days, as was the case in the flood of the upper Gila River in
January, 1916. For the determination of the probability of long-duration
storms, the recurrence-interval of various total amounts of precipitation in
periods greater than 24 h r was derived by tabulating the highest rainfall
amounts each year t h a t fell on two or three consecutive days, arranging the
terms in order of magnitude, and platting as in the studies of 24-hr rains.
These arrays were prepared for a limited number of stations, each of which
was chosen to represent a certain area with characteristic topographic relief
and elevation.
This analysis showed that the ratio of the total rainfall in a 48-hr period
to that falling in a 24-hr period is essentially constant regardless of the recurrence-interval of the rain, and similarly, the ratio of 72-hr total to 24-hr is
approximately constant. At any given recurrence-interval the amount of
rain in any consecutive 48-hr period is about lOv0 to 20% greater than the
24-hr amount expected, and the total for any 72 consecutive-hr period is 20y0
to 30% greater than the amount in 24 hr.
These ratios are only an indication of the relation between 1-day, 2-day,
and 3-day rains, since the present analysis did not include sufficiently detailed
studies of long-duration rains and winter intensity patterns to form the basis
for positive statements on this subject. The rains experienced in the Pecos
River watershed of eastern New Mexico in Septemher, 1941, indicate that,
a t least in that section of the state, summer-type rainfalls of very high amounts
may fall on two consecutive days.
C O M P A R I S O N OF
MAGNITUDE
O F 1-DAY,%DAY,
AND $DAY
ACKNOWLEDGMENTS
The writer gratefully acknowledges the assistance of Thomas Maddock, Jr.,
for suggestions during the progress of the study, B. T. Mitchell in checking
original records, and a number of workers of the Work Projects Administration,
principally the late E. F. Blanchard, who copied data from the original ohservers' records and assisted in the frequency tabulations. The cooperation
of E. L. Hardy and G. K. Greening, U. S. Weather Bureau, in allowing access
to the original records of cooperative observers is appreciated.