A thunderstorm that produces large amounts of rain in a short amount of time may lead to flash floods. Flash flooding is the number one thunderstorm killer. Nearly 140 fatalities occur nationally each year. Seventy-five percent of flash flood fatalities occur at night; half of the victims die in automobiles or other vehicles. Two feet of running water is enough to carry away most vehicles. Many deaths occur when persons knowingly drive around barricades indicating that the road is washed out ahead.

In August of 1994, two separate flooding events occurred in Minnesota. In Redwood and Lincoln counties, up to 8 inches of rain fell. In McLeod County, 7 inches of rain occurred in a short period of time. In both events, no lives were lost, but millions of dollars in damages were reported to homes, roads and bridges.