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FEMA Updates Flood Maps in Imperial, Riverside and San Diego Counties

Release Date Release Number

OAKLAND, Calif. — The Federal Emergency Management Agency (FEMA) is updating portions of Imperial, Riverside and San Diego County flood maps in 2021. The new maps identify the current flood hazards in the Oasis drainage area located west and northwest of the Salton Sea that help building officials, contractors and homeowners make effective mitigation decisions, thereby contributing to safer and more resilient communities.

Before the new Flood Insurance Rate Maps (FIRMs) become effective, there is a 90-day appeal period from Feb. 25, 2021 to May 26, 2021. During that time, residents with technical and scientific information, such as detailed hydraulic or hydrologic data, can appeal the flood risk information on the preliminary maps. View the preliminary FIRMs at fema.gov/preliminaryfloodhazarddata.

Flood hazards are dynamic and change frequently for many reasons, including weather patterns, erosion and community development. Officials from FEMA, Imperial, Riverside (via the Coachella Valley Water District), and San Diego counties worked together to collect new data and provide updated information about alluvial fans in the Oasis drainage area to better reflect the flood risk. These changes may also affect future building standards or insurance requirements.

The local mapping project is part of a national effort led by FEMA to increase local knowledge of flood risks and support actions to address and reduce the effects of flooding on new and improved structures. FEMA encourages residents to review the preliminary flood maps to learn about local flood risks, potential future flood insurance requirements and identify any concerns or questions about the information provided.

Risk of flooding affects almost every corner of the nation. In total, 98% of counties have experienced a flood event, which makes floods the most common and widespread of all weather-related natural disasters.

For more information, contact Imperial County at (442) 265-1736 or jim.minnick@co.imperial.ca.us, Riverside County via the Coachella Valley Water District at (760) 398-2651 or SStrosnider@cvwd.org, or San Diego County at (858) 495-5417 or Mehdi.Khalili@sdcounty.ca.gov.


FEMA’s mission is helping people before, during, and after disasters. Follow FEMA Region 9 online at twitter.com/femaregion9.

Last updated February 26, 2021