Mapping the Flood Risk

Flood Insurance Rate Maps
The county partnered with Federal Emergency Management Agency (FEMA) to update and digitize the flood insurance rate maps for Snohomish County. The newly updated and digitized Flood Insurance Rate Maps (FIRMs) were released on September 28, 2010, and the adoption process is pending.

Risk MAP
The county is now partnering with FEMA on a detailed coastal study. This is a project within the FEMA program known as Risk MAP. Risk MAPs products and services go beyond the traditional FIRMs by including flood risk data and assessment tools that can contribute to citizens’ understanding of risk and enable communities to enhance their mitigation plans and actions.

Coastal Study

In 2010, FEMA began a study of 74 miles of coastline in Snohomish County. The county is partnering with FEMA on the project.

The project will update flood hazard data in the FIS and FIRM for the areas in Snohomish County subject to coastal flooding. Additional products of the Coastal Study will include a flood risk database, flood risk report, and Risk MAP. These three products will provide information that includes:
  • Areas of higher flood risk by census block
  • Areas of highest expected damage
  • Potential future losses to existing structures
  • Areas within and upstream of the watershed that may be contributing to flood risk and associated interrelationships
  • Improved risk quantification figures for mitigation planning
The information generated by this project will be useful to planners, developers, community officials, and emergency managers to support mitigation planning and improved design and construction standards for development in coastal areas.

More information on the project, including the schedule and map, is available in the Snohomish County Coastal Project Summary.

As noted in the summary, preliminary information may be available as soon as December 2013. 

Technical Support Data Notebooks (TSDNs)
Available TSDNs for flood mapping projects completed in Snohomish County are listed below: