There is an average of 29 tornadoes per year in Illinois. Illinois led all other states in 1998 in the number of tornadoes. Thunderstorms can produce strong winds, lightning, hail or heavy rain. Each year, more people are killed by lightning than by tornadoes. Twenty-one people have been killed by lightning since 1985 in Illinois.
Thunderstorms are most likely to happen in the spring and summer.
In Illinois, severe thunderstorms frequently occur in the late afternoon or evening. Large hail does extensive damage to property and crops every year. In 1998, hail 4V2 inches in diameter was reported northwest of Rushville and at Arthur. Floods can take several hours to days to develop. Twenty people in Illinois have died from floods since 1985.