- A tornado is defined as a violently rotating column of air in contact with the ground.
- Although tornadoes occur in many parts of the world, they are frequently found in the United States east of the Rocky Mountains during the Spring and Summer. In an average year, 800 tornadoes are reported nationwide, resulting in 80 deaths and over 1,500 injuries.
- Tornadoes have occurred in every month of the year, but in the Tri-State area, they are most common during the months of May, June and July.
- Tornadoes can also occur at any time of the day, but are most common during the late afternoon and early evening hours.
- The most violent tornadoes are capable of tremendous destruction with wind speeds of 250 mph or more. The Chandler/Lake Wilson, MN tornado of June 16, 1992, was an example of one of these violent tornadoes. Damage paths with the violent tornadoes can be in excess of one mile wide and 50 miles long.
- Some tornadoes may form during the early stages of rapidly developing thunderstorms. This type of tornado is most common in the High Plains' states.
- Tornadoes may appear nearly transparent until dust and debris are picked up.
- Occasionally, two or more tornadoes may occur at the same time.
- The average tornado moves from the southwest to the northeast, but tornadoes have been known to move in any direction.
- Strong straight-line winds can cause damage that can be mistaken for that caused by a tornado. Straight-line winds can easily exceed 70 mph.
Recent Violent Tornadoes in the Tri-State Area
- Manchester, SD - June 24, 2003
- Spencer, SD - May 30, 1998
- Comfrey, MN - March 29, 1998
- Chandler/Lake Wilson, MN - June 16, 1992