Tornadoes in Illinois

A s one of the major weather hazards in Illinois, tornadoes are responsible for a grim statistic: Illinois leads the nation with the most tornado-related deaths—1,364 since 1916. Tornadoes can occur anywhere and at any time; being prepared, once a warning is issued, is very important for self protection. Fortunately, early warning systems for tornadoes are now much more accurate than they were a few years ago. What, where and when? A tornado is a tightly swirling circular vortex of air rotating counter-clockwise at speeds of 200 to 600 mph at the ground. These high winds destroy what they hit and shower debris around and away from the funnel, creating damages and deaths in the storm’s path. Tornado funnels assume a wide variety of shapes ranging from rope-like horizontal shapes to wide, black clouds. Funnels are not always obvious if the cloud base is close to the ground. Tornadoes originate in a large thunderstorm that has a strong vertical flow of air (updrafts) and strong crosswinds aloft. These two winds are found only in a few large thunderstorms, but when present, they create an in-cloud rotation of air that grows downward to the ground, forming a tornado. The average tornado in Illinois lasts 25 minutes, travels 13 miles and has a funnel that is 185 yards wide. Studies of many Illinois tornadoes have revealed there are three types: small, moderate and huge. Small tornadoes represent 42 percent of all tornadoes. The average small tornado varies from 1 to 2 miles in length and has a funnel only 150 feet wide. Twin tornado funnels generated