** Update, 1/14, 5:45PM: Flood Watch upgraded to Flood Warning for the Snoqualmie River at Carnation. River rising slightly higher than previously expected. Minor flooding is forecast. The river will rise above flood stage around 7PM tonight and crest near 54.6ft at 4AM Saturday. 54ft is flood stage. At that level the river will flood much of the farmland and several roads from Fall City downstream into Carnation and Duvall. The river will fall below flood stage Saturday morning. **
The King County Flood Warning Center opened shortly after noon on Thursday, January 13th, to monitor rising flows on the Tolt River from heavy rainfall in the area. After Wednesday’s heavy snowfall and days of steady, sometimes heavy rain, The National Weather Service has also issued a Flood Watch for numerous Washington Rivers – including the Snoqualmie. A flood watch means flooding is a possibility, not imminent.
As of 12:45PM yesterday, the North Fork of the Tolt River was flowing at 2,650 cubic feet per second (cfs). The threshold for a Phase II flood alert level on the mainstem Tolt River is 2,500 cfs and is typically associated with minor flooding. A Phase II flood alert level is when the King County Flood Warning Center activates to monitor conditions.
This morning minor flooding of the Tolt River closed West Snoqualmie River Rd NE between NE 24th and NE Tolt Hill Rd due to water over the roadway.
According to National Weather Service, a series of wet Pacific storms will bring periods of heavier rain to Western Washington over the next 5 days. The heaviest rains are predicted for Sunday. Forecasts call for 2 – 5 inches over the area on Sunday. Forecasts for tonight into Saturday call for 1 – 3 inches of rain. The freezing level is expected to stay between 5,000 – 9,000 feet. That mean all precipitation in the mountains will be rain and cause snow pack melting – putting additional pressure on the Snoqualmie River.
According to the latest forecasts, the Snoqualmie River is listed as one area river at greatest risk of flooding. Current forecasts of the timing and location of the heaviest rainfall are quite variable so uncertainty of flooding on any specific river is moderately high.
To monitor possible flooding in the Snoqualmie Valley you can visit www.kingcounty.gov/flood for the latest real-time river level information. Any changes or upgrades to the flooding status will also be updated here.