Tornadoes are rapidly rotating columns of air that form from a thunderstorm above them and are in contact with the ground. This rapid rotation is what makes them different from all other thunderstorm wind types.
Tornado winds can be much stronger than other severe storm winds, and in fact they are the fastest winds on earth. The strongest tornadoes have been measured at over 318 miles per hour.
All tornadoes are very damaging and can be deadly. Any Tornado Warning should be treated as a life safety situation. To find out about Tornado Watches and Warnings, severe weather warning sources such as Outdoor Warning Sirens, severe weather emergency plans for your home or business, and tornado safety, visit Ramsey County’s Getting Ready page.
In Minnesota we get an average of 42 tornadoes a year, mainly in May and June, though we have had tornadoes in every month, even January. Ramsey County has had nine tornadoes since 1963, including the 1965 F4 Mounds View/Columbia Heights/ Fridley tornado that killed six people. Visit the Minnesota Tornado History Project to learn more about the tornadoes in Minnesota history.
Facts about tornadoes
- A rapidly rotating column of air coming from a thunderstorm, but not touching the ground is known as a funnel. Only when there is proof that this rotation has touched the ground – such as a cloud of debris forming – can we call it a tornado.
- Most tornadoes are only about 200 to 300 yards wide and last less than 15 minutes, but they can be much larger and last longer. The record width is 2.6 miles wide. Some tornadoes have lasted several hours on the ground.
- The strongest, largest and longest lived tornadoes (EF 4 and 5 on the Enhanced Fujita Scale) are very rare – fewer than one percent of all tornadoes are that strong.
- 99 percent of all tornadoes rotate counterclockwise.
- Tornadoes normally occur on the back side of a storm, after the rain and hail. From the front part of the storm you would not be able to see any tornadoes coming because of the rain covering up your view. This is why you should never drive through a strong thunderstorm: you don’t know what you are driving into.
- Tornadoes can change direction – even reverse course or move in a different direction than the storm above them. They can also change speed and size rapidly. They can move as fast as 60 miles per hour on the ground. It is best to stay far away from a tornado so that there is no chance you are close enough to get hit by it if it suddenly changes direction.