Tornado Facts

  • A tornado is a violently rotating column of air extending from a thunderstorm to the ground.
  • Although tornadoes occur in many parts of the world, they are found most frequently in the United States.  In an average year, 1,200 tornadoes cause 70 fatalities and 1,500 injuries nationwide.
  • Nationwide, Michigan has the third highest average number of tornado deaths per year with a total of over 237 since 1950. During this time, over 668 tornadoes occurred in the state, the majority in southern lower Michigan.
  • Tornadoes can occur at any time of the day or night and in 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 3:00-9:00 p.m.
  • Tornadoes usually come from the southwest at speeds of 20-40 mph. However, they have traveled at speeds near 70 mph.
  • The average tornado is on the ground less than 10 minutes and travels a distance of about five miles. However, they have stayed on the ground for more than three hours and traveled more than 200 miles.
  • The width of the tornado as it touches the ground averages 300 to 400 yards but may be wider.
  • Tornadoes wind speed vary from 100 mph to nearly 300 mph.
  • Tornadoes usually develop from thunderstorms and normally occur at the trailing edge of the storm.
  • Tornadoes do their destructive work through the combined action of their strong rotary winds, flying debris and the partial vacuum in the center.


Updated 1/04/10