- Floods and flash floods are the leading weather-related killers in the United States.
- A flood watch means flooding is possible and a flood warning means flooding is imminent.
- General river flooding occurs after long-term heavy rain, snow melt, or a combination of the two. It usually occurs slowly, allowing more time to move people and property to safety.
- Flash flooding is always life threatening and occurs very quickly. Flash flooding typically occurs in hilly or mountainous areas, but can occur anywhere when heavy rains fall in a short amount of time. Flash flooding can also be caused by a dam failure.
- Urban and small stream flooding is a more subtle flood threat. It can occur when heavy rain falls in an urban or rural area, resulting in flooding streets, underpasses, or drainage ditches in an urban area, or creeks in rural areas. It is not normally a threat unless motorists drive through the flooded road or children lay in flooded drainage ditches. Small stream flooding can be hazardous if people get too close to a swollen creek.
NWS Weather Forecast Offices