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Tornadoes
Information for the Public
What is a severe thunderstorm?
A severe thunderstorm produces large hail that is one inch in diameter or larger, damaging
winds of 58 mph or greater, and/or a tornado.
What is a tornado?
A tornado is a column of violently rotating winds extending down from a thunderstorm cloud
and touching the surface of the earth.
What is the difference between a tornado and a funnel cloud?
A funnel cloud is also a column of violently rotating winds extending down from a
thunderstorm; however, it does not touch the earth as a tornado does.
How many tornadoes usually occur in Michigan every year?
An average of 16 tornadoes occur in Michigan each year. Since 1950, 243 persons have been
killed due to tornadoes. During this same time, Michigan has experienced 950 tornadoes.
When do tornadoes generally occur?
Most tornadoes occur during the months of May, June, July, and August primarily in the late
afternoon and evening hours. However, tornadoes can occur anytime of the day or night in
almost any month during the year.
How fast do tornadoes travel?
Tornadoes generally travel from the southwest at an average speed of 30 mph. However, some
tornadoes have very erratic paths, with speeds approaching 70 mph.
How far do tornadoes travel once they touch the ground?
The average Michigan tornado is on the ground for less than ten minutes and travels a distance
of about five miles. However, they do not always follow the norm and have been known to stay
on the ground for more than an hour and travel more than 100 miles.
When is a tornado or severe thunderstorm watch issued?
A tornado or severe thunderstorm watch is issued whenever conditions exist for severe
weather to develop. Watches are usually for large areas about two-thirds the size of Lower
Michigan and are usually two-to-six hours long. Watches give you time to plan and prepare.
