Minor flooding expected along middle Green River as King County continues flood response

Tolt up to Phase IV, Snoqualmie still at Phase III flood alert level

Planned water releases from a flood-control dam in the upper Green River watershed will lead to increased flows downstream – including some minor flooding in the middle reach of the Green above Auburn Sunday evening. Meanwhile, the Tolt River has reached a Phase IV flood alert level, with major flooding possible in the Carnation area.

The King County Flood Warning Center, which has been monitoring river flows since 2 a.m. Sunday, has issued a Phase II flood alert level for the Green River, which is expected to be flowing at 7,000 cubic feet per second (CFS) at Auburn by 10 p.m. Sunday.

The targeted 7,000 CFS flow is a combination of planned releases from Howard Hanson Dam, plus the natural inflow from streams that empty into the Green River between the dam and the City of Auburn.

At this flow, very minor flooding could be expected in the largely rural and sparsely populated agricultural area of the Green River Valley upstream of Auburn. No river flooding is expected farther downstream, including in the cities of Auburn, Kent, Renton or Tukwila.

The Tolt River rose to a Phase IV flood alert level at 1:15 p.m. Sunday, when flows at the gage in Carnation exceeded 7,000 CFS. At this level, swift floodwaters could overtop levees near Carnation and shifts in the river channel could occur.

The Snoqualmie River remains at a Phase III flood alert level, with moderate flooding expected throughout the Snoqualmie Valley. As of 1 p.m., the sum of the Snoqualmie River’s three forks was 25,250 CFS, solidly above the 20,000 CFS threshold for a Phase III flood alert level. Overtopped roads and road closures could be expected at this flood alert level.

King County flood patrol crews are observing conditions in several watersheds, and will continue their patrols until conditions improve.

Flood Warning Center staff will monitor stream gages and weather reports, and will provide updated information on river conditions as necessary. Real-time river level information is available online at http://www.kingcounty.gov/flood.

Updated information on flooding will also be posted on the King County website at www.kingcounty.gov, or via RPIN, the area's regional website at http://www.rpin.org. A recorded flood-information hotline is also updated each hour for citizens wanting information in flood areas. The number is 206-296-8200 or 1-800-945-9263.

Citizens who need help interpreting flood information should call 206-296-4535 or 1-800-768-7932. Problems on County maintained roads can be reported by calling 206-296-8100 or 1-800-KC-ROADS.

Motorists are strongly advised to heed all road closure and detour signs; driving through flooded streets is the number-one cause of deaths during flood events.

A new, automated flood alert system is now available and provides real-time warning of potential high water on more than a half-dozen rivers. King County residents and business owners can sign up to receive King County Flood Alerts by visiting www.kingcounty.gov/flood, or by calling 206-263-3400 during regular business hours to register by phone. Messages of potential high flows on any of King County’s major river systems can be sent by phone, text or e-mail.

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The King County Flood Control District is a special purpose government created to provide funding and policy oversight for flood protection projects and programs in King County. The Flood Control District’s Board is composed of the members of the King County Council. The Water and Land Resources Division of the King County Department of Natural Resources and Parks develops and implements the approved flood protection projects and programs. Visit http://www.kingcountyfloodcontrol.org for more information.

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