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Flood Hazard Maps

To find flood hazard maps in your area:

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Flood Risks

Do you live or work in a floodplain? Flood hazard maps help determine the flood risk to your home or business.
More about flood risks
The Department of Ecology highly recommends contacting the community Floodplain Administrator, Community Development Director, or Public Works Department for specific flood risks and regulations.

Flood Insurance Rate Maps (FIRMs):

FIRMs outline flood hazards in a community. A FIRM may include flood insurance risk zones, 1% and 0.2% annual chance floodplains, floodways, base flood elevations or depths, roads, streams, and more. They are developed by FEMA.


Data comes in two forms:

  • DFIRM database product: Digital FIRM. These are gradually being updated by county.
  • Digital Q3 flood data product: The current FIRM if there is no DFIRM for a county.

MAP TERMS

Floodway:

Stream channel, plus floodplain areas, that must be kept free from building so the 1% annual chance of flood can occur without increasing flood heights.


1% annual chance flood:

1% annual chance of flooding may be equaled or exceeded in any given year (100 year flood).


0.2% annual chance flood:

A 0.2% annual chance of flood in any given year (500 year flood).

flood diagram
High-risk zones are areas that have a 1% chance of flooding each year.
If you live in a Special Flood Hazard Area or high-risk area and have a Federally-backed mortgage, your mortgage lender requires you to have flood insurance.
More about flood insurance
 
Coastal Atlas Version 5.0
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