A powerful atmospheric river brought record rainfall to parts of Washington and Oregon states in the Pacific Northwest of the USA from 04 December 2023.

As of 05 December, two fatalities were reported. Dozens of homes have been flooded and several people rescued, including some by Coast Helicopter teams.

Rain and Rivers

The National Weather Service (NWS) in Seattle reported significant rainfall totals in various parts of Western Washington, including the Olympic National Park which recorded 8.67 inches / 220.22 mm of rain in 24 hours to 05 December 2023. Weather stations at Hoodsport and Duvall both recorded 7.12 inches / 180.85 mm during the same period.

NWS Seattle also reported daily rainfall records in Hoquiam, Forks, Sea-Tac Airport and Olympia Airport. The 4.69 inches / 119.126 mm of rain that fell in 24 hours in Forks, WA, is more than double the previous daily rainfall record set in 1971, and more rain than Las Vegas, NV has received in all of 2023 so far.

The Stillaguamish River reached a record high of 21.34 feet / 6.50 metres at Arlington on 05 December, beating the previous high of 21.16 feet / 6.44 metres reached in 2010.

As of 05 December, the Skagit River was above Major Flood stage near Concrete. The Snohomish, Snoqualmie, Skokomish and Cowlitz were above Moderate Flood Stage in several locations.

Rescues and Flood Damage

The US Coast Guard helicopter teams rescued four people from a flooded home and another person from a vehicle trapped in flood waters near Rosburg, Washington, on 05 December.

Fire crews recued 4 people from a flooded home on Monroe, Washington. Another person was rescued from a vehicle trapped in floods in Granite Falls, Washington, where at least 12 homes have been flooded.

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