Rain lifts Tolt River to Phase IV flood alert level; Snoqualmie River, Issaquah Creek at Phase III

Hard rain from a strong tropical storm continues to hammer portions of King County, leading to potentially significant and widespread river flooding.

The King County Flood Warning Center has issued a Phase IV flood alert for the Tolt River, with flooding expected throughout much of the watershed, and a Phase III flood alert level for both the Snoqualmie River and Issaquah Creek, where moderate flooding is now possible.

At 2 a.m. Wednesday, the Tolt River near Carnation was flowing at 9,500 cubic feet per second (cfs) – well above the Phase IV flood alert level of 7,000 cfs. At this level, levees could overtop near Carnation, and major roadways could be closed because of fast, deep floodwaters.

Flows the Snoqualmie River and Issaquah Creek have also been climbing quickly because of heavy rainfall. As of 2 a.m., the sum of the three forks of the Snoqualmie River was 25,210 cfs and climbing, well above the 20,000-cfs threshold for a Phase III flood alert level.

At this flow level, flooding of varying depths could be expected across the Snoqualmie Valley, and major roadways could be affected by the flooding, including the Fall City -Carnation Road, Tolt Hill Road and Novelty Flats Road.

Also reaching a Phase III flood alert level early Wednesday morning was Issaquah Creek, which could experience moderate flooding.

Motorists are reminded to obey all emergency road closure signs. The number-one cause of fatalities in flooding is from people who ignore emergency road closure signs and who drive into deep, swift water.

The King County Flood Warning Center has been open since 4:30 p.m. Tuesday to monitor rising river levels. The center will remain open and continue to monitor the river flooding until conditions improve.

Flood Warning Center staff are monitoring stream gauges and weather reports, and will provide updated information on river conditions as necessary. Flood patrol crews are also monitoring conditions from the field.

Flood Warning Center staff will continue to monitor stream gauges and weather reports and provide updated information on river conditions as necessary.

Real-time river level information is available online at http://www.kingcounty.gov/environment/waterandland/flooding/warning-system.aspx.

Updated information on flooding will also be posted on the King County Web site at www.kingcounty.gov, or via RPIN, the area's regional Web site 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.

Related information

Flooding Services and Information

River and Floodplain Management Section

Water and Land Resources Division