Flash flooding is the number one weather-related killer in the United States. Flooding kills almost twice as many people each year as tornadoes and hurricanes combined! Unlike hurricanes, floods are a threat in every state.
Most flash flooding is caused by slow-moving thunderstorms, thunderstorms repeatedly moving over the same area (called "training"), or heavy rains from hurricanes and tropical storms.
Nearly half of all flash flood deaths are auto-related. Even 6 inches of fast-moving flood water can knock you off your feet and at a depth of 2 feet will float your car.