Tornado Alley

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Tornado Alley
Teacher Guide
This activity discusses the patterns and impacts
of tornadic storms. Students will review the
seasonal patterns across the United States in the
first part of the activity and will focus on a
specific tornado event from Moore, Oklahoma, in
2003 for the second segment.
Overview
Standards
Grade 8 Standards
P1.3, P4.3
Oklahoma PASS Objectives
High School Physical Science Standards
P4.1
Science Content Standards
National Science Education Standards
Content Standard D Earths History Content
Standard F Science and Society
Middle School. Can be modified with additional
questions for higher levels.
Grade Level
Intermediate. Some prior knowledge of ArcView
tools is assumed.
GIS Skill Level
Students should have some experience with aerial
photo interpretation.
Other Skills
Should be completed in one 50-minute class.
Time
This activity can be modified for features in
other areas of the country if alternative data
sources are available.
Teacher Note
Tornado Alley
Teacher Guide 1
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Tornado Alley
Teacher Guide
Materials
This activity relies on several GIS datasets.
The files and the designed directories are listed
below
C\ESRI\Projects\Tornado
C\ESRI\ESRIDATA\USA
8may2003_fscale.shp
Torn1b.shp
Torn5.shp
Cities.shp
Torn7.shp
Torn3.shp
9may2003_fscale.shp
okcnty.shp
Winterbuffer.shp
Fujita.avl
Equinbuffer.shp
states.shp
Tornado.apr
Roads.avl
Summerbuff.shp
C\ESRI\Projects\2003 Aerials\Oklahoma
C\ESRI\ESRIDATA\USA\OK
naip1-1_ok109_2003.sid
R2000CLE.shp
R2000OKL.shp
Sources

• KANGIS kangis.org/community/search/
• GEMS Lesson Plan Search Blown Away by Tom
  Baker
• National Weather Service, Norman, OK
  www.srh.hoaa.gov/oun/storms
• May 8, 2003 Central Oklahoma Tornadoes
  ArcView Shapefiles
• Geo Information Systems www.geo.ou.edu
• Oklahoma County - Roads Tiger 2000 (R2000.shp)
• Cleveland County Roads Tiger 2000 (R2000.shp)
• Oklahoma Center for Geospatial Information -
  www2.ocgi.okstate.edu
• Oklahoma County 2003 Aerial Photo

Lesson Preparation
This project utilizes two Data Frames in ArcGIS
9.x. The first displays data obtained from the
Blown Away Lesson from KANGIS. US seasonal
tornado patterns are the focus of the first view.
The second view contains data related to the May
2003 tornado in Moore, Oklahoma. The view
contains local aerial photography as well as
storm data from the National Weather Service.
Some scale-based view limits can be set on the
layers to help speed up the refresh within the
project.
Developed by Steve OConnell geographilia_at_hotmail.
com
Tornado Alley
Teacher Guide 2
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Tornado Alley
More tornadoes strike the United States than any
other nation on Earth, and in the United States,
Tornado Alley is the center of the action. From
Texas northward through the Plains of Oklahoma,
Kansas, and Nebraska, residents of Tornado Alley
are more likely to experience a tornado than
people in the rest of the nation. The seasonal
pattern of tornadic activity reveals a more
diverse distribution of violent weather. The
migration of the upper-level jet stream and
boundaries between the cold Canadian air and warm
Gulf Moisture produce a more varied pattern than
many people expect.
In this activity you will examine seasonal data
for historic tornadoes across the nation. You
will compare the concentrations of tornadic
weather from one month to another and relate that
to the normal weather for that time of year. In
addition, you will also look at the effects of
one particular tornadic event Moore and
Oklahoma City, Oklahoma, May 8 9, 2003.
Estimated tornado strengths, damage paths, and
aerial images of debris are all part of the
analysis.
Radar Base Reflectivity image near Tinker AFB
from 2225 UTC, May 8, 2003
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Step 1
Getting Started
To begin, open ArcGIS 9.1 by selecting the icon
on your desktop.
At the Welcome menu, select An Existing Map
and click Browse for Maps.
Navigate to the following directory c\esri\proj
ects\Tornado
Open the tornado.mxd file.
Tornado Alley
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Step 2
Nationwide Tornado Patterns
When your project opens you should see the main
project window, displaying a two Data Frames
Oklahoma May 2003 US Jet Stream Patterns. The
US Jet Stream Patterns frame should be active.
In this view, you will see four themes of Tornado
activity one for January, March, May, and July.
Each of these themes contains point data for
tornados occurring in the respective month from
1950 to 1990. Turn on the Tornado January
theme.
1. Describe the locations and
concentrations of tornadoes during January. In
what state do the most intense (F3 or higher)
tornadoes occur? MISSISSIPPI
2. Describe the locations and
concentrations of tornadoes during May. In what
states (name three) do the most intense (F3 or
higher) tornadoes occur? ANSWERS INCLUDE
OKLAHOMA, KANSAS, NEBRASKA, IOWA, TEXAS
3. Describe the locations and
concentrations of tornadoes during July. In
what states (name three) do the most intense (F3
or higher) tornadoes occur? ANSWERS INCLUDE
NORTH DAKOTA, SOUTH DAKOTA, MINNESOTA, NEBRASKA,
IOWA
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Step 3
Tornadoes and Seasonal Weather
Most scientists believe there is a strong
correlation between seasons and the development
of tornadoes. One of the key components of
seasonal change is the location of the
upper-level jet stream. The jet stream is a
river of air located in the atmosphere that
helps to move weather systems in a general West
to East direction across the United States.
As the year moves from winter to summer, the jet
stream migrates from south to north, altering the
dynamics of weather from coast to coast. In your
ArcView activity, there are three jet stream
themes, one winter, one summer, and one equinox
(for both spring and fall). These graphics show
the generalized position of the seasonal jet
stream.
4. Do you see a relationship between the
location of the Winter Jet Stream and January
Tornadoes? YES THEY ARE BOTH NEAR THE GULF COAST
5. Do you see as strong a relationship
between the location of the Equinox Jet Stream
and May Tornadoes? NOT AS STRONG
6. What about between the location of the
Summer Jet Stream and July Tornadoes? MORE THAN
EQUINOX BUT NOT WINTER
7. Which of the three seasonal jet
streams shows the strongest relationship to
tornado location? WINTER IS STRONGEST
8. Other than the jet stream, what other
influences (weather or otherwise) may can cause
different patterns of tornadoes? TOPOGRAPHY,
TEMPERATURE
Tornado Alley
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Step 4
Oklahoma Tornadoes
Now that you have seen some of the general
patterns of tornadoes across the United States,
we will take a look at a specific event in
Oklahoma. In the past several years, the city of
Moore, south of Oklahoma City, has been hit by
two major tornadoes. The first occurred on May
3, 1999 and was one of the largest and most
intense tornadoes in Oklahoma history.
The second came as part of a two day outbreak on
May 8 and 9, 2003. The path of the 2003 tornado
followed almost exactly the path of the 1999
storm. In ArcGIS, switch the Data Frame from US
Jet Stream to Oklahoma May 2003. (Right-click on
Oklahoma May 2003 and select Activate.)
The tornadoes we are looking at happened in
Oklahoma and Cleveland Counties. Zoom to these
counties in your view. When you zoom in, you
should see the road layers for each county
appear, along with the tracks for the May 8 9
tornadoes. We want to focus on the May 8th
tornado. Zoom to only the May 8th track.
Step 5
The Fujita Scale
Tornadoes are classified using a system known as
the Fujita Scale. The Fujita scale ranges from 0
to 5 with higher number representing
progressively more damaging storm forces. On the
last page of this activity, there is a chart
displaying information on the different Fujita
classifications.
Now, we want to reclassify the track to display
the different Fujita, or F-values along the
damage path. Open the Layer Properties menu and
change the Symbology to Quantities/Graduated
Colors with F_scale as the Value Field. Select a
color ramp in a shade of red. Click OK. The
tornado track should now be several shades of
red, with the darkest color representing the
highest Fujita value.
9. What is the highest F-value for this
tornado track? 4
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Step 5
The Fujita Scale, cont
10. What would be the top wind speed for
this tornado? 260 MPH
11. According to the Fujita Scale, what
kind of damage would be expected with this type
of tornado? DEVESTATING DAMAGE HOUSES
LEVELED/STRUCTURES WITH WEAK FOUNDATIONS BLOWN
AWAY SOME DISTANCE/LARGE MISSILES
Step 6
GIS Analysis of Tornado Damage Extents
GIS can be an important tool for emergency
personnel and damage assessment teams who are
evaluating the area after a tornado hits.
Officials will want to know how big the tornado
was, where it first touched down and finally
dissipated. In addition, the specific location
of damaged or destroyed structures can be
determined using aerial photographs.
Using your Identify tool and your measure tool,
answer the following questions about the tornado
damage track. (When looking at the track, answer
questions based on the main track, not the small
segment to the southwest.)
12. Near what intersection does the May
8th tornado first touch down? S SANTA FE NW
5TH
13. Near what intersection does the May
8th tornado finally dissapate (use the closest
major intersection)? S INDIAN MERIDIAN E RENO
14. How wide is the widest part of the
damage path, in meters? 760M (25)
Tornado Alley
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Step 7
Air Photo Analysis
Your view of the May 8th tornado also includes
the color DOQQ for Oklahoma County. This image
includes the damage path for this tornado, even
though most of the path is in Cleveland County.
Turn on the Oklahoma County 2003 DOQQs theme and
zoom into the area near the start of the damage
path, close to Interstate 35.
15. Can you see the damage path in the
photo? What types of structures (residential,
commercial, industrial, etc) appear to be the
hardest hit? MOSTLY RESIDENTIAL
Zoom to the area where the tornado crosses
Interstate 40. The tornado at this point had
been on the ground for some time and was, at some
points, as high as an F4.
16. Are there as many structures damaged
here as there were in the area around I-35?
What kind of damage is more evident here? NO
MOSTLY VEGETATION/TREES FIELDS
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Table 1
The Fujita Scale
Table from The Online Tornado FAQ by Roger
Edwards, NOAA/NWS Storm Prediction Center, Norman
Oklahoma
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