King County Flood Warning Center issues Phase 4 flood alert for Tolt River as more rain sends river levels higher

February 1, 2020

Summary

The King County Flood Warning Center issued a Phase 4 flood alert for the Tolt River at 7:30 a.m. on Saturday, Feb. 1, with severe flooding possible along the river upstream of Carnation. The Flood Warning Center opened at 8:30 a.m. on Friday, Jan. 31, to closely monitor river conditions as a powerful storm dumped several inches of rain across the region.

Story

As significant rainfall continues across much of the region, the King County Flood Warning Center issued a Phase 4 flood alert for the Tolt River at 7:30 a.m. on Saturday, Feb. 1, with severe flooding possible – including levee overtopping and road closures along the river near Carnation. 

As of 7:30 a.m. Saturday, the Tolt River at Carnation was flowing at 8,740 cubic feet per second (CFS), slightly higher than the Phase 4 flood alert threshold of 8,500 CFS. At these flows, levees can overtop near Carnation, seepage underneath levees could increase, river channel changes can occur upstream of Carnation, and additional road closures are possible. 

The Snoqualmie River remains at a Phase 3 flood alert level, with moderate widespread flooding in the Snoqualmie Valley that has resulted in road closures. As of 7:30 a.m. Saturday, the sum of the Snoqualmie River’s three forks was 30,220 CFS, well above the Phase 3 flood alert threshold of 20,000 CFS. 

The White River remains at a Phase 2 flood alert level, resulting in possible minor flooding along the river at Pacific. As of 7:30 a.m. Saturday, the White River below Mud Mountain Dam was flowing at 5,440 CFS, which is slightly higher than the Phase 2 threshold of 5,000 CFS.
 
A King County flood patrol spent the overnight hours in the field, monitoring flood conditions and reporting information back to the Flood Warning Center, which has been open since 8:30 a.m. on Friday, Jan. 31. 

Flood Warning Center employees 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 kingcounty.gov/flood.

During river flooding events, King County serves as a clearinghouse for information on flood conditions, operating a recorded message center with continuous updates of river gauge readings and flood phases and other related information. Reach the Flood Warning Center at 206-296-8200 or 1-800-945-9263. Interpreter assistance in multiple languages is available.

King County offers free access to KC Flood Alerts, an automated system that allows subscribers to receive customized alerts of potential flooding for any or all of King County’s seven major river systems.

Find the KC Flood Alerts link at kingcounty.gov/flood. This website also features the latest information about river levels and road conditions, plus weather reports and other critical links.

For help with flooding on smaller streams or urban drainage problems, call 206-477-4811 during business hours, or 206-477-8100 after hours or on weekends.

Problems on County maintained roads can be reported by calling 206-477-8100 or 1-800-KC-ROADS.

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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. Information is available at kingcountyfloodcontrol.org.