skip to main content

Find comprehensive services related to flood preparation, warnings, response and recovery-- and also planning to minimize risks from future floods in King County, Washington.

To offer a suggestion or report an error on the King County flooding services and information website, please contact Fred Bentler, webmaster.

Flooding services and information in King County, WA

Flooding services and information

Look up real-time flood conditions and subscribe to flood alerts for the Snoqualmie River, Tolt River, Skykomish River, Raging River, Issaquah Creek, Cedar River, Green River, and White River and learn the severity of flooding to expect at different flood phases based on past flood events.

Learn what to do before, during and after a flood. Look up, locate, and order flood hazard maps. Print the page and keep it on hand just in case.

Road conditions and closures map
Look up roads that are closed from water over the roadway or flood damage from an interactive map of King County.

Report a water quality or drainage problem
Use the phone number or an online form to request an investigation into water quality and drainage problems in King County. This page also contains background information to help residents understand how problems are handled.

Floodplain mapping
Review the latest floodplain boundaries in King County and look up or order maps from various sources.

Flood related facts in King County as of 2010:

  • 2010 marked the 50th anniversary of the King County Flood Warning Program;
  • There are approximately 8,000 parcels located in a King County floodplain;
  • River flooding has led to 11 presidentially declared disasters in King County since 1990;
  • The leading cause of flood-related deaths is from motorists driving through standing water or around barricades or road-closure signs.

2008-2009 winter flooding video image
Video: Winter flooding, 2008-2009 season (external link, 44.47 min.) Video
Get Windows Media Player (external link) needed to watch this video.
Learn how storms and weather affected King County last winter (2008-2009) and how King County responds to flood emergencies.

River levee vegetation policy video An examination of levee vegetation policy Video
Video of Ron Sims keynote speech to the U.S. Army Corps of Engineers’ Seattle district levee vegetation policy symposium, presented on February 26, 2009.
Windows Media format, video length 47 minutes, 23 seconds
Text transcript, An examination of levee vegetation policy

Flood protection - King County performance measures
This measure describes the flood hazard risks reduced through the King County flood protection program.

King County Flood Control District
Learn about the purpose, governance structure and schedule of activities for this recently established flood management district.

Community Rating System
Learn about a National Flood Insurance Program (NFIP) incentive program that encourages communities to accurately assess risks and reduce flood losses, and rewards better flood management with reduced insurance premiums for its residents.

King County Code >> Critical Areas (Acrobat PDF format)
County definitions and rules on development standards, restrictions, and requirements as well as permitted uses in King County floodplains and other sensitive areas. Codes pertaining specifically to floodplains can be found under sections 21A.24.230 to 21A.24.275 of this document.

Interactive map - water-related sensitive areas
Note: this link will open a new browser window
Pick the King County map layers you want and click the "refresh map" button located at at the bottom of the layers list to display floodways, 100-year floodplains, channel migration hazard areas, parcels and other map-based information. Viewing information about individual map features may take some practice: choose the "active" (or queryable) map layer from the layers list, select the Arc IMS Query Tool tool, and click on one of that layer's features to display associated data.

Interactive map - stormwater complaints, facilities, projects and studies
Note: this link will open a new browser window
Zoom in to view the full set of the County's map layers including drainage complaints, the regional, commercial and residential stormwater facilities, neighborhood drainage projects, stormwater studies, and aerial imagery among other things. Viewing information about individual map features may take some practice: choose the "active" (or queryable) map layer from the layers list, select the Arc IMS Query Tool tool, and click on one of that layer's features to display associated data.

Flood related video interview by Kim Hill with Larry Phillips, Kathy Lambert, Mark Isaacson
Watch Video:
Preventing flood disasters, (22.22 min.) Video
RealPlayer needed to watch this video.

Flood warnings and alerts

Flood Buyout and Home Elevation Program
This page answers frequently asked questions about King County's program to buy houses located in floodplains or provide homeowner assistance in having homes elevated. The page also provides information about related programs that can help homeowners affected by flooding.

City of Snoqualmie hazard mitigation planning (external link)
Find public process documents for an update to the city's 2003 multi-hazard mitigation plan including meeting agendas, minutes, and documents including some covering flood mitigation.

Shoreline management
Learn about King County's program to protect shorelines, promote public access, and establish priorities for shoreline uses along shorelines and flood areas of county's large rivers.

Hydrologic Information Center
This page provides local rain and stream gage data and flood reports for King County river basins including the Cedar River, Snoqualmie River, Issaquah Creek, Bear Creek, and Green River Basins. The page provides current information about water levels as well as reports about flooding in years past.

Take Winter by Storm
Find breaking storm news and a directory of resources for Seattle-King County residents.

Stormwater retention/detention (R/D) facilities
Learn why King County requires, maintains and inspects facilities that catch and slowly release stormwater that drains from our residential areas.

Combined Sewer Overflow (CSO) Control Program
Learn what King County is doing to eliminate the discharge of raw sewage that may result from stormwater exceeding the capacity of combined sewers, and read a map showing where such discharges may occur.

Erosion control for construction sites
This page provides information for about how to prevent runoff at construction sites during the wet season, from the Dept of Development and Environmental Services.

Natural hazards: flooding
This page is published by the King County Office of Emergency Management. The page provides background information about flooding in King County, including background flooding information, history, vulnerabilities and effects.

Documents

2006 King County Flood Hazard Management Plan
The 2006 King County Flood Hazard Management Plan sets forth a ten-year strategy for how King County proposes to manage its rivers and floodplains to minimize flooding and channel migration hazards throughout the county. The 2006 Plan establishes policy, program and project recommendations to improve public health and safety, and to minimize risks to people, property, roads, public infrastructure, and natural resources. The 2006 Plan does not propose any changes to current flood hazard regulations.

The connection between floodplains and the economy
Learn about the economic effects of flooding on King County businesses and the region's overall economy.

South Fork Snoqualmie River Gravel Removal Study New!
Evaluates the effectiveness of gravel removal for reducing floods on the South Fork Snoqualmie River upstream of the North Bend Boulevard (Bendigo) Bridge.

Erosion and sediment control standards
Appendix D of the King County Surface Water Design Manual. 1 MB Adobe Acrobat file.

Snoqualmie flood-farm task force report
Provides finding and recommended mechanisms to help Snoqualmie Valley farms that get periodically flooded, in ways that maintain good floodplain management and continue salmon recovery in the lower Snoqualmie River.

King County Climate Change Plan
How King County seeks to reduce greenhouse gas emissions, adapt to projected climate change impacts, and embed mitigation and adaptation into county policy decisions. The plan incorporates issues, goals and actions related to flooding.

» Other flooding-related documents

Projects

Lake Allen Outlet Project
Culvert work to alleviate roadway flooding.

Lower White River countyline reach flood projects
Levee setback projects to increase flood storage and reduce the risk of flood damage during high-water.

Lower Tolt River Floodplain Restoration Project
Overview of a habitat restoration project designed to return the lower Tolt River to its historic meandering state and rich habitat diversity while continuing to provide flood protection and park uses.

Related information

Related agencies

News and announcements

Feb. 2, 2012
Expert review of river and floodplain projects recommends more, earlier public engagement

2010-2012 Midterm Report (pdf)
King County Executive Dow Constantine

Jan. 30, 2012
Flood Warning Center closes, as rain eases and Snoqualmie River flows recede

Jan. 29, 2012
Flood Warning Center opens as river levels rise

Jan. 27, 2012
King County’s residents weigh in on river management priorities through survey

Dec. 30, 2011
King County closes Flood Warning Center as Green River flows stabilize

Dec. 29, 2011
King County opens Flood Warning Center as Green River rises from dam releases

Dec. 29, 2011
King County closes Flood Warning Center as Snoqualmie River flows recede

Dec. 28, 2011
King County opens Flood Warning Center as Snoqualmie River rises from heavy rain

Dec. 21, 2011
External article, Seattle P-I
Environmental groups sue US over flood management

Nov. 17, 2011
King County research of river conditions to help public safety, habitat on Tolt River

Oct. 24, 2011
Agencies reaffirm King County’s high credit ratings ahead of bond sale

Oct. 10, 2011
King County public meeting for Lake Allen flooding remedy update set for Oct. 29

Oct. 6, 2011
Flood-fighting pumps returning to Pacific as King County prepares for storm season

Fall 2011
New flood phases on Cedar, Tolt rivers
King County has adjusted the flood phases on the Cedar and Tolt rivers to more accurately reflect observed flooding impacts during high river flows. Flood Alerts will be issued using the latest flood phase thresholds.

Sept. 30, 2011
Flood Awareness Month gains urgency as potential exists for second La Nina winter

Sept. 30, 2011
Two King County organizations honored with first-ever Executive’s Awards for Community Preparedness

Sept. 27, 2011
External opinion, Seattle Times
Howard Hanson, a dam site better

Sept. 16, 2011
King County Executive, City Mayors hail announcement on Howard Hanson Dam
Call for continued collaboration and vigilance on emergency preparedness

Aug. 15, 2011
External article, Tukwila Reporter
Engineers run more tests at Howard Hanson Dam along Green River

July 12, 2011
External article, Seattle Times
FEMA won't pick up $30 million tab to prepare for flooding

May 26, 2011
External report, KUOW Weekday
How Do We Prevent Flood Damage Here? audio

May 5, 2011
Executive Constantine, Flood Control District praise signing of legislation protecting flood funds
City Mayors join Constantine, Patterson in thanking Legislature for work after Governor signs EHB 1969

April 21, 2011
Executive Constantine proposes next wave of King County actions to reduce greenhouse gas emissions and respond to climate change
Motion addresses near-term actions to reduce greenhouse gas emissions and prepare for local impacts such as sea level rise and flooding

April 14, 2011
Executive Constantine goes online April 18 to discuss climate change with experts, public

April 7, 2011
April 28 meeting in Vashon to discuss new flood maps, coastal shoreline study

Mar. 30, 2011, 9 p.m.
Controlled releases from dam expected to push Green River to Phase II flood alert level

Mar. 30, 2011, 3:50 p.m.
Snoqualmie River up to Phase III flood alert; as rain continues in portions of King County

Mar. 30, 2011, 12:50 p.m.
Tolt River rises to Phase III flood alert level; King County monitoring rain-swollen rivers

Mar. 30, 2011, 10:30 a.m.
Snoqualmie River rises to Phase II flood alert level; wet weather continues in King County

Mar. 30, 2011. 8:30 a.m.
King County Flood Warning Center opens to monitor rising Tolt River flows

Mar. 9, 2011
External article, SnoValley Star
State Legislature saves flood control district funding

Mar. 9, 2011
External article, The News Tribune
For the health of Puget Sound, floodplains must be healthy

Feb. 11, 2011
Help available for farmers interested in building, repairing livestock-saving farm pads
King County schedules Feb. 28 meeting in Preston to offer advice, technical help

Jan. 25, 2011
External article, Mother Jones
Why Seattle Will Stay Dry When Your City Floods

Public Meetings: FEMA Flood Insurance Rate Maps
Auburn, Renton, Kent Jan. 26, Jan. 27, Feb. 7

Puget Sound starts here

Archived flooding news
Website mini-survey

Yes | No | Other