Why are severe thunderstorms so dangerous?
Many hazardous weather events are associated with thunderstorms. Fortunately, the area affected by any one of them is fairly small and, most of the time, the damage is fairly light. Lightning is responsible for many fires around the world each year, as well as causing deaths when people are struck. Under the right conditions, rainfall from thunderstorms causes flash flooding, which can change small creeks into dangerous raging water in a matter of minutes, washing away large boulders and most man-made structures. Hail up to the size of softballs damages cars and windows, and kills wildlife caught out in the open. Strong (up to more than 120 mph) straight-line winds associated with thunderstorms knock down trees and power lines. In one storm in Canada in 1991, an area of forest approximately 10 miles wide and 50 miles long was blown down. Tornadoes (with winds up to about 300 mph) can destroy all but the best-built man-made structures.
