Tornados aren't the only hazards associated with thunderstorms. Hail, flash floods and lightning can all be deadly. Hail forms as small objects like ice pellets, water droplets or even insects are circulated by powerful winds inside the storm cloud. Since these storms can reach tens of thousands of feet high, their tops are well below feeezing. With each trip from top to bottom, the object picks up another coating of ice and gets bigger. Eventually, this pellet is too heavy to be kept aloft by the winds and it falls to earth as a hailstone.

One of the requirements for a severe thunderstorm is hail at least three-quarters of an inch in diameter, which is about the size of a penny. But hailstones can be much larger. Golfball, softball and even grapefruit-size hail have been recorded. Since a hailstone can fall at about 100 miles per hour, you can imagine the severe damage hail can cause. In fact, hail causes about a billion dollars in damage to crops and property each year.