TORNADO FAQ
Tips for Tornado Safety


Tornado Facts

    1. An average of 16 tornadoes occur in Michigan a year. Since 1950, a total of 237 persons have been killed due to tornadoes. During this time, 668 tornadoes have occurred in the state.

    2. Tornadoes can occur at anytime of the day or night and in almost any month of the year. However, most tornadoes occur in the months of April, May, June and July in the late afternoon and evening hours usually between 3-7pm.

    3. Tornadoes usually come from the western horizon and have been known to travel at speeds of up to 70 mph.

    4. Tornadoes that develop from thunderstorms that occur early in the season have a tendency to be the most intense.

    5. The average tornado is on the ground less than 10 minutes and travels a distance of about 5 miles. However, they have stayed on the ground for more than three hours and traveled more than 200 miles.

    6. The width of the tornado as it touches the ground averages 200 to 400 yards but may be wider, up to one mile across.

    7. Tornadoes usually turn counter-clockwise with wind speeds that vary from under 100 mph to approaching 300 mph.

    8. Tornadoes develop from dark thunderstorm clouds and research has shown that many tornadoes occur toward the southwestern edge of the thunderstorm cloud.

    9. The greatest frequency of tornadoes occurs during temperatures between 70 and 75 degrees with high relative humidities.

    10. Tornadoes do their destructive work through the combined action of their strong rotary winds, flying debris, and the partial vacuum in the center of the vortex.

Return to Top of Screen

Technically, What is a Tornado?

Return to Top of Screen

What Terms Are Used to Warn You?

Return to Top of Screen

How Much Time is Needed to Warn You?

The following table shows the different steps in the warning process and the time required for each step.

TIME FOR EACH STEP
(minimum to maximum)
TOTAL ELAPSED TIME
(minimum to maximum)
Identification 5 sec - 2 min 5 sec - 2 min
Report to First Level Warning Center - Police, Fire, CD 30 sec - 3 min 30 sec - 5 min
Sound Sirens 30 sec - 2 min 1 min - 7 min
Report to Weather Service 30 sec - 4 min 1.5 min - 11 min
Warning Decision 30 sec - 5 min 2 min - 16 min
NOAA Weather Radio 30 sec - 3 min 2.5 min - 19 min
Teletype to TV and Radio Stations 3.5 min - 5 min 6 min - 24 min
Broad cast from TV & Radio to Public 1 min - 6 min 7 min - 30 min

This table illustrates that, even under ideal conditions, a tornado may be on the ground for 7 minutes before commerical radio or TV could begin to warn the population. Even more astonishing is the fact that, currently it requires about 30 minutes to warn half the population through the electronic media. Since the average tornado lasts approximately 10 minutes chances are it could strike your home without warning. Therefore, individuals and communities should be prepared to warn themselves. How can you improve the odds of being warned in time?