Tornado Fact Sheet
Although tornadoes occur in many parts of the world, these destructive forces of nature are found most frequently in the United States east of the Rocky Mountains during the spring and summer months. In an average year, 800 tornadoes are reported nationwide, resulting in 80 deaths and over 1,500 injuries. A tornado is defined as a violently rotating column of air extending from a thunderstorm to the ground. The most violent tornadoes are capable of tremendous destruction with winds speeds of 300 m.p.h. or more. Damage paths can be in excess of one mile wide and 50 miles long. Once a tornado in Broken Bow, Oklahoma, carried a motel sign 30 miles and dropped it in Arkansas!
Thunderstorms develop in warm, most air in advance of eastward-moving cold fronts. These thunderstorms often produce large hail, strong winds and tornadoes. Tornadoes in the winter and early spring are often associated with strong frontal systems that form in the Central States and move east. Occasionally, large outbreaks of tornadoes occur with this type of weather pattern. Several states may be affected by numerous severe thunderstorms and tornadoes.
Tornado Stats
- Tornadoes are most likely to occur between 3 and 9 p.m., but have been known to occur at all hours of the day and night.
- The average tornado moves from southwest to northeast, but tornadoes have been known to move in any direction. The average forward speed is 30 m.p.h. but may vary from nearly stationary to 70 m.p.h.
- According to the National Weather Service in Chanhassen, the Twin Cities Metro Area experienced 114 tornadoes between 1950 and 1999 (includes the counties of Anoka, Scott, Carver, Sherburne, Dakota, Washington, Hennepin, Wright and Ramsey).
TORNADO WATCH: Tornadoes are possible in your area. Remain alert for approaching storms.
TORNADO WARNING: A tornado has been sighted or indicated by weather radar. If a tornado warning is issued for your area and the sky becomes threatening, move to your pre-designated place of safety.
Information adapted from: A Preparedness Guide. A joint publication of NOAA, FEMA and The American Red Cross. January 1994.
