Name ___________________ Date _ _ _ _ Class _ _ _ __
Physical Geography of the United States and Canada
DiHerentiated Instruction
Tornado Alley
A tornado is a violent, twisting column of air. It emerges from
within a thundercloud and reaches down to the ground. Tornadoes
can come in many shapes, but they usually form in the shape of a
funnel. Some have wind speeds of up to 450 miles (724 km) per hour.
Most tornadoes in the United States form in an area called
"Tornado Alley." This area includes parts of several states, shown
on the map below. Although tornadoes occur throughout the United
States, especially along the Gulf Coast from Texas to Florida, people
often think of the Great Plains
when they hear about tornado
Tornado Alley
activity.
Why do so many tornadoes
form in Tornado Alley? The
most destructive tornadoes
originate from strong, rotating
thunderstorms called supercells.
The geography of the Great
Plains is a perfect breeding
ground for supercells. The land
in this region is relatively flat.
This allows cold, dry, polar air
from Canada to meet warm,
moist, tropical air from the Gulf
of Mexico. Most tornadoes form
400 miles
along the front-or meeting
place-between these two air
masses.
Spring is the most active time for tornadoes. During this time of
the year, tornadoes form mainly within Tornado Alley and east into
the Ohio Valley. In summer, tornado activity moves mainly to an area
extending from North and South Dakota into Pennsylvania and New
York. Winter tornadoes usually form along the Gulf Coast. Tornadoes
have been seen in alISO states.
Directions: On a separate sheet of paper, answer the following
questions.
1. Identifying What is a supercell?
2. Theorizing Although tornadoes can form in any state, they rarely occur
in the northeastern part of the United States. Why do you think this is so?
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Teaching Strategies for Different Learning Styles
The following activities are ways the basic lesson can be modified to
accommodate students' different learning styles.
English Learners (EL)
Ask students to define the term Tornado
Alley [the area of the United States where most
tornadoes occur], and have them explain the
significance of the shaded part of the map.
[The shaded section denotes Tornado Alley.] Also
ask students if their community is located
within Tornado Alley.
Verbal/Linguistic; Intrapersonal
A storm chaser is a person who intentionally seeks out severe storms such as tornadoes.
Many storm chasers simply want to see the
event, though some are scientists who follow
storms to conduct research. Storm chasing is
particularly popular in the Great Plains. Ask
students to prepare a report about this activity.
Visual/Spatial
Assign students to create tornado-themed
art that depicts the power of the storm and
typical geographic features found in Tornado
Alley.
Kinesthetic
Directions for creating "homemade tornadoes" are easy to find online. Allow students
to make a "tornado in a bottle" and demonstrate it in class. Students should explain how
their creations are similar to the storms that
occur in Tornado Alley.
Logical/Mathematical
The Fujita Tornado Damage Scale is used
to rate the intensity of a tornado. It examines
the damage caused by a tornado after it has
passed over a human-made structure. Ask
students to create a table categorizing the
different levels of the scale. Also ask them
to create two circle graphs: one showing the
percentage of all tornadoes since 1960 (or some
other specific period) that were weak (FO-Fl),
strong (F2-F3), or violent (F4-FS); and one
showing the percentage of deaths caused by
these levels of tornadoes. What conclusions
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can they draw from the data? (Roughly 74%
of all tornadoes are weak, 25% are strong, and 1%
are violent- but 67% of deaths come from violent
storms.)
Visual/Spatial
Tornado Alley has no agreed-upon boundaries. The map accompanying the article is just
one representation. Ask students to find and
map another version of Tornado Alley based
upon different criteria. Display students' maps
in the class.
Advanced Learners
The April 3-4, 1974, Super Outbreak was
the largest known outbreak of tornadoes in the
United States, with 148 tornadoes forming in
11 states. Assign students to write a three-page
report about this event.
Verbal/Linguistic; Interpersonal
Tornadoes have been prominently featured
in a number of movies, stories, and songs.
Divide the class into three groups, and have
them use library or Internet resources to compile lists of as many of these as they can find.
Share the lists in class to see who found the
most.
Auditory/Musical
Invite students to compose a song that
either (1) explains how tornadoes form, or
(2) explains the steps to take in the event of
a tornado. Allow students to perform their
compositions in class.
Below Grade Level
Ask students to use library or Internet
resources to find the difference between a
tornado watch and a tornado warning. Have
them explain the difference in a paragraph.