Tornadoes are the most feared and admired aspects of a thunderstorm. Recently, many North Dakotans got a front-row view when on the evening of August, 15th, 2022, two touched down in rural ND at the same time.
Since 1950, North Dakota has seen as few as two tornadoes a year to as high as sixty. We average about twenty-three a year.
But what makes these violent columns of air form? First, we need a thunderstorm, but not just any thunderstorm. We need a supercell thunderstorm — a very strong storm with particularly violent winds.
Winds at different heights of the atmosphere will be at different speeds. The upper air winds will often be much stronger, forming a rotating column of air.
In supercell thunderstorms, the updrafts are very strong. So strong, in fact, that they’ll lift that rotating column of air into the storm and form what’s called a mesocyclone. This is a very powerful rotating column of air inside the storm.
Pretty soon, the base of the storm will lower. This forms the wall cloud.
A funnel cloud will drop from the base of the wall cloud. It stays a funnel cloud until it officially touched the ground. That’s when it’s then classified as a tornado.