Controlled water releases from dam expected to send Green River to Phase II flood alert level

King County Flood Warning Center open and monitoring minor flood flows

The King County Flood Warning Center has issued a Phase II flood alert for the Green River, as heavy rainfall that continues to pummel the region brings minor flooding to a handful of rivers.

Based on planned water releases from Howard Hanson Dam, the Green River is expected to exceed the Phase II flood alert threshold by 6 a.m. Sunday. Only minor flooding is likely to occur, and only in the rural areas without levees upstream of Auburn. These increased flows are not expected to have any impact to the cities of Auburn, Kent, Renton or Tukwila.

King County opened its Flood Warning Center early Sunday morning to monitor rising flows on several King County rivers, including the Snoqualmie and Tolt rivers, which have both reached the Phase II flood alert level.

As of 2:30 a.m., the Tolt River was flowing at 3,810 cubic feet per second (CFS). Typically, only minor flooding would be expected at this flow.

Meanwhile, at 2:30 a.m. the sum of the Snoqualmie River’s three forks was at 18,190 CFS. At this flow level, minor lowland flooding would be expected in low-lying areas along the Snoqualmie River.

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.

An 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.

Related information

Flooding services and information

Snoqualmie-Skykomish Watershed

How to prepare for a flood

King County Water and Land Resources Division