• Background

Public Education

Tornado Facts

1.  What is a tornado?

It is a column of violently rotating winds extending down from a thunderstorm cloud and touching the surface of the earth.

2.  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.

3.  How many tornadoes usually occur in Michigan every year?

An average of 18 tornadoes occur in Michigan each year.   Since 1950, 239 persons have been killed due to tornadoes.  during this same time, Michigan has experienced 782 tornadoes.

4.  When do tornadoes generally occur?

Most tornadoes occur during the months for June, July and August in the late afternoon and evening hours.  However, tornadoes can occur anytime of the day or night in almost any month during the year.

5.  How fast do tornadoes travel?

Tornadoes generally travel from the southwest and at an average speed of 30 miles per hour.  However, some tornadoes have very erratic paths, with speeds approaching 70 mph.

6.  How far do tornadoes travel once they touch the ground?

The average Michigan tornado is on the ground for less than 10 minutes and travels a distance of about 5 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.

7.  What is a tornado "WATCH"?

A tornado/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 prepare.

8.  What is a tornado "WARNING"?

A tornado warning is issued by the local National Weather Service (NWS) office whenever a tornado has been sighted or NWS Doppler Radar indicates a thunderstorm capable of producing a tornado.  A severe thunderstorm warning is issued whenever a severe thunderstorm is observed or NWS Doppler Radar indicates a thunderstorm capable of producing damaging winds or large hail.  Warnings are for smaller areas, such as counties, and are usually 30 minutes to one hour in length.   You must act immediately when you first hear the warning.  If severe weather is reported near you, seek shelter immediately.  If not, keep a constant lookout for severe weather and stay near a shelter.

9.  How do I find out about a warning if my electricity is already out?

In some areas, civil emergency sirens will be your first official warning.  However, you may also receive warnings directly from the National Weather Service broadcast over NOAA Weather Radio, as long as you have a model with a battery backup.


Tornado Characteristics

Time of day during which tornadoes are most likely to occur is mid-afternoon, generally between 3 and 7 p.m., but they have occurred at all times of day.

Direction of Movement is usually from southwest to northeast.(Note:  Tornadoes associated with hurricanes may move from an easterly direction.)

Length of Path  average 4 miles, but may reach 300 miles.  A tornado traveled 293 miles across Illinois and Indiana on May 26, 1917, and lasted 7 hours and 20 minutes.

Width of Path averages about 300 to 400 yards but tornadoes have cut swatches a mile or more in width.

Speed of Travel  averages from 25 to 40 miles per hour, but speeds ranging from stationary to 68 miles per hour have been reported.

The Cloud  directly associated with a tornado is a dark, heavy cumulonimbus (the familiar thunderstorm cloud) from which a whirling funnel-shaped pendant extends to the ground.

Precipitation  associated with the tornado usually occurs first as rain just preceding the storm, frequently with hail, and as a heavy downpour immediately to the left of the tornado's path.

Sound occurring during a tornado has been described as a roaring, rushing noise, closely approximating that made by a train speeding through a tunnel or over a trestle, or the roar of many airplanes.