El Nino Snow/Ski Data – And, to Boot – A Warm November?
11/11/2015
El Nino Snow/Ski Data – And, to Boot – A Warm November?
So El Nino is in the house for this winter, or, are we in El Nino’s house? Warm water in the Pacific near
the equator and Central and South America that affects our weather. The Godzilla of El Ninos I heard on
‘CCO a few weeks ago…the strongest one since 1997-98. The last El Nino event was in 2009-2010.
The National Oceanic and Atmospheric Administration (NOAA) climate prediction has our winter in the
Twin Cities being warmer than normal with equal chances for precipitation.
I looked at the Twin Cities Climate data (MN DNR website) for the El Nino years since the winter of 18991900. There have been 27 El Nino events since then including the current one. There have been 28 La
Nina (colder) and 62 Neutral events in that time period as well.
It should be noted that not all El Nino events are the same. The intensity and peak of the events are
different. I did not differentiate between them for the below.
El Nino winters here have average 40.8 inches of snow and about 59 natural snow ski days (2 inches of
snow on the ground). La Nina winters are 49.5” and 79 days and Neutral winters are 48.5” and 68 days.
Our natural snow ski seasons are about 10 weeks, 70 days, here in the Twin Cities. On the average, El
Nino winters have about 8 inches less snow and about 10 days less in the natural snow ski season.
El Nino winters have ranged from a low of 14.2 inches of snow in 1930-31 and only 13 ski days to a high
of 84.1 inches of snow and 123 ski days in 1991-92 (remember the Halloween Blizzard). Other notable El
Nino winters include 1986-87 with 17.4 inches and 15 ski days, 1951-52 with 79 inches and 106 ski days
and 1969-70 with 63.4 inches and 106 ski days.
The last strong El Nino in 1997-98 had 45 inches of snow and 37 ski days. The last El Nino in 2009-10 had
40.7 inches of snow and 92 ski days.
For comparison the 26 El Nino winters have had 3 winters with 100 plus ski days (mentioned above), 8
with 40 days or less and 9 with 70 days or more. The 28 La Nina winters have had 9 with 100 plus, 3 with
40 or less and 18 with 70 or more. The Neutral winters have had 14 with 100 plus, 15 with 40 or less and
29 with 70 or more.
Along with the short term oscillation that is El Nino (about 6 to 18 months) there is also the PDO or
Pacific Decadal Oscillation. The PDO is a long-lived El Nino like pattern of Pacific climate variability that
can last for 20 to 30 years. The PDO has a warm phase and cool phase. We are currently entering a
warm phase.
The below table summarizes the El Nino years since 1950 for which we have PDO index data. Ski start is
the approximate start of the ski season (days from November 1 – this is difficult to arrive at as do you
count a few early days with snow on the ground as part of the ski season when it melts for a week or
two). Snow intervals are periods of snow with melting in between. ONI is the Oceanic Nino Index which
indicates the strength of the El Nino episode during that year’s winter. The PDO is for December,
January and February with the PDO average for those months following. This year (2015) the last ONI
number was 1.5 for July-August-September and the PDO was 1.94 in September 2015.
Mark Lahtinen
Page 1 of 4
El Nino Snow/Ski Data – And, to Boot – A Warm November?
El Nino
Winter
19511952
19571958
19631964
19651966
19691970
19721973
19761977
19821983
19861987
19871988
19911992
19971998
20022003
20062007
20092010
Dec - Feb
11/11/2015
ski start
PDO
avg.
Temp
1-Nov
Ski Days
79
17.33
48
106
4
0.7
PDO (D, J, F)
-1.68, -2.01, .46
21.2
21.25
19
19
3
1.7
-.57, .25, .62
0.1
28.9
17.77
39
59
4
1
-1.08, .01, -.21
-0.43
36.1
15.85
63
46
4
1.6
0.06, -.82, -.03
-0.26
63.4
13.71
39
106
1
0.7
1.38, .61, .43
0.81
41.7
16.61
32
92
1
2.1
-0.76, -.46, -.61
-0.61
43.6
11.85
33
70
3
0.8
1.22, 1.65, 1.11
1.33
74.4
23.97
58
70
3
2.3
.26, .56, 1.14
0.65
17.4
25.64
90
15
3
1.3
1.77, 1.88, 1.75
1.8
42.4
16.52
49
66
2
1.2
1.27, .93, 1.24
1.15
84.1
23.56
1
123
3
1.8
.09, .05, .31
0.15
45
25.77
73
37
3
2.5
.67, .83, 1.56
1.02
35
19.18
90
35
2
1.5
2.10, 2.09, 1.75
1.98
35.5
21.01
62
68
3
1.2
.14, .01, .04
0.06
40.7
16.57
39
92
1
1.4
.08, .83, .82
PDO 1.94 in
Sept.
0.58
2015-2016
Snow
Ints
Oni
Index
Tot
Snow
1.5 JAS
-1.38
From the above there is a very slight negative correlation (R2 = .0558) between the ONI index and ski
days. There is no correlation between ONI and total snow (melting intervals?) For the PDO index there is
a slight negative correlation (R2 = .207) between the PDO and ski days and a very slight negative
correlation (R2 = .0962) between PDO and total snow – again melting intervals? See graphs below.
Mark Lahtinen
Page 2 of 4
El Nino Snow/Ski Data – And, to Boot – A Warm November?
11/11/2015
Perhaps of more concern right now is the current warm November we’re in. We are currently (as of
11/11/15) 10+ F above normal and on track to possibly be one of the top 5 warm Novembers on record
at least through the middle of the month. (I know things could change in a hurry). Below is a table of the
top 15 warm Novembers on record. Five of them were also El Nino episodes. The following winter total
snow and ski days are shown as well as the ENSO event (El Nino Southern Oscillation).
The average total winter snow following these warm Novembers is 36 .5 inches with an average of
about 53 ski days.
Mark Lahtinen
Page 3 of 4
El Nino Snow/Ski Data – And, to Boot – A Warm November?
Warm Nov.
2001
2009
1999
1899
1931
1913
1922
1923
2011
1953
1934
1917
1878
1904
1954
1963
Avg.
Nov.
Avg.
T
46.4
42.7
41.8
41.2
40.3
40.2
39.6
39.5
39.2
39.3
38.8
38.8
38.7
38.6
38.3
38.3
641.7
40.1
ENSO
Neutral
El Nino
La Nina
El Nino
Neutral
El Nino
La Nina
Neutral
La Nina
Neutral
Neutral
Neutral
El Nino
La Nina
El Nino
Following
Tot.
Snow
66
40.7
36.2
36.4
46.6
22.5
42.2
32.4
22.3
25.7
51.6
30.8
Following
31.1
33.9
28.9
547.3
36.5
52
101
59
790
52.7
11/11/2015
Ski Days
26
92
55
31
69
25
58
43
21
11
84
63
33.7
On November 11, 2014 there was 3 inches of snow on the ground (which was gone by 11/23/14). It was
colder as man-made snow was being produced and Elm Creek opened up the short loop on November
19, 2014.
We’ve got 1 to 2 inches of rain coming which would have been a whopper of a snow storm if it was
about 10F colder. However, it is supposed to get back up into the 50s and possibly 60 by Sunday…still
too warm to make snow. 2015 is also on track to be the warmest year on record globally.
The weather can change quickly and there are some good winters in the above. I’m sure it will cool
enough so that we’ll be skiing on the man-made at least by early December which is typical for the
opening of Elm Creek.
As stated above the NOAA climate prediction has warmer than normal winter temperatures and equal
chances for precipitation. The questions are will that precipitation fall as rain or snow and will there be
melting intervals? Time will tell.
NOAA has a good discussion of the winter:
https://www.climate.gov/news-features/blogs/enso/what-expect-winter-noaa%E2%80%99s-outlook-reveals-what-conditions-are-favored
Mark Lahtinen
Page 4 of 4