Summary (tl;dr)

Western Washington, including Seattle, is bracing for multiple atmospheric river events next week, bringing significant rainfall and a high risk of widespread river flooding, urban flooding, and landslides.

Essential Background

Seattle and the broader Puget Sound region are accustomed to heavy winter rainfall. However, climate change is intensifying these weather patterns, leading to more frequent and extreme precipitation events, which, combined with rising sea levels, increases the area's vulnerability to severe flooding and associated hazards like landslides.

The Full Story

A series of atmospheric river events is forecast to impact Western Washington from Monday through Wednesday of next week, with forecasters anticipating 2-6 inches of rain in lowlands and 5-11 inches in mountain regions. This heavy precipitation, compounded by elevated snow levels, is expected to cause significant river flooding. Several rivers, including the Skagit, Skykomish, Snohomish, Snoqualmie, and Cowlitz, are projected to reach moderate to near-major flood stages, potentially leading to the worst flooding on the Snoqualmie River since March 2022 and on the Snohomish River since 2020. Urban areas, particularly Seattle, face a high risk of localized flooding due to overwhelmed storm drains, and the entire region is under an increased threat of landslides as soils become saturated. A rare flood watch has been issued for all of Western Washington, extending from Sunday through Friday. Coastal areas, especially in Whatcom County, are also preparing for potential tidal flooding due to exceptionally high "king tides" coinciding with the storms.

Why It Matters

The impending severe weather and flood risks pose a serious threat to public safety, infrastructure, and private property across Western Washington. Significant disruptions are expected, including potential road closures, damage to homes and businesses, and the need for residents in flood-prone areas to prepare for possible evacuations. The recurrence of such intense weather patterns highlights the ongoing challenges of climate change and the critical need for continued adaptation and resilience strategies in vulnerable regions like Seattle.

Geographic Location

• Seattle, King County, Washington, United States (expected urban flooding, heavy rainfall, and landslide risk)
• Western Washington, United States (widespread atmospheric river events, increased landslide risk, region-wide flood watch)
• Skagit River, Skagit County, Washington, United States (forecast to reach moderate to near-major flood stage)
• Skykomish River, Snohomish County, Washington, United States (forecast to reach moderate to near-major flood stage)
• Snohomish River, Snohomish County, Washington, United States (forecast to reach moderate to near-major flood stage, worst flooding since 2020 near Monroe)
• Snoqualmie River, King County, Washington, United States (forecast to reach near major flood stage, worst flooding since March 2022 near Carnation)
• Cowlitz River, Cowlitz County, Washington, United States (forecast to reach moderate flood stage)
• Whatcom County, Washington, United States (threat of landslides and river/tidal flooding, coastal flood advisories, particularly Cherry Point and Birch Bay)
• Birch Bay, Whatcom County, Washington, United States (high tides above 10 feet)
• Cherry Point, Whatcom County, Washington, United States (flirting with moderate or higher flood levels from tidal flooding)
• Friday Harbor, San Juan County, Washington, United States (flirting with moderate or higher flood levels from tidal flooding)