Flash Flood Guidance

National Weather Service CNRFC Guidance
In Contra Costa County, storm runoff  comes fast and the water raises quickly in creeks. Residents and businesses lack time to prepare once a large storm is upon us.

The National Weather Service California Nevada River Forecast Center (CNRFC) produces several on-line products to inform the public on weather related issues. Flash Flood Guidance Maps are one of these products.

The Flash Flood Guidance Maps provide a map view of Contra Costa County colored similar to other maps they produce such as the Quantitative Precipitation Forecast (QPF) map. The Flash Flood Guidance can be generally summarized as follows:

Flash Flooding can occur when we experience...

  • Approximately 1 inch in one hour
  • Approximately 2 inches in three hours
  • Approximately 3 inches in six hours

Review the Flash Flood Guidance maps and become familiar with other weather links. Prepare early if you live in a flood prone area.