A multi-day atmospheric river event affecting western Washington, United States, since March 15, 2026, is elevating flood potential as cumulative rainfall and snowmelt impact the regional river basins. Prolonged precipitation and high snow levels are leading to rising rivers, with flood risk expected to persist through early March 21.
A prolonged atmospheric river is affecting British Columbia this week, with Flood Watch, multiple rainfall warnings, and Special Weather Statements in effect across parts of the province. Some coastal areas could receive up to 400 mm (15.7 inches) of rain, while heavy rain on existing snowpack is increasing the risk of flooding, washouts, landslides and dangerous avalanche conditions.
A stalled atmospheric river over the Pacific Northwest is forecast to deliver 127–254 mm (5–10 inches) of precipitation to parts of Washington between March 17 and 20, 2026. High freezing levels above 2 100 m (7 000 feet) will result in rainfall across most elevations, accelerating snowmelt and increasing the likelihood of riverine flooding.
Heavy snowfall caused multiple vehicle spinouts and crashes on I-90 at Snoqualmie Pass in Washington, forcing authorities to close the highway in both directions on March 13 and keep it closed overnight into March 14, 2026. Snoqualmie Pass received about 56 cm (22 inches) of new snow overnight, while the Summit at Snoqualmie reported about 107 cm (42 inches) over 48 hours during the storm.
An atmospheric river made landfall in the Pacific Northwest during the morning of March 11, 2026, bringing heavy rain and snow across portions of Washington and Oregon. Forecasts show that the event will continue affecting the region through early March 14, producing significant precipitation totals, flooding concerns, and major winter weather impacts in mountainous terrain.
Two atmospheric rivers are forecast to hit the Pacific Northwest beginning late March 10, 2026, bringing heavy rainfall to coastal areas and significant snowfall to higher elevations in Washington and Oregon. Precipitation totals of 180–380 mm (7–15 inches) are forecast in mountainous regions, with the potential for river rises and localized flooding through the week.
A slow-moving low-pressure system is forecast to bring long-duration atmospheric river conditions to the U.S. West Coast between Saturday, February 21, and Wednesday, February 25, 2026, delivering heavy precipitation from Washington to California. The strongest impacts are expected across southern Oregon and northern California Coast Ranges and the Klamath Mountains, where 5-10 inches (125-250 mm) of rain is forecast.
Atmospheric river associated with a slow-moving low-pressure system is forecast to impact California between February 21 and 26, 2026, bringing another round of heavy precipitation to the state. The Center for Western Weather and Water Extremes (CW3E) indicates very high confidence (>90%) in atmospheric river conditions along northern California through February 23, with moderate-to-high confidence of the AR conditions shifting south along the coast by February 24.
Two mid-level troughs with associated surface lows are forecast to bring widespread precipitation to California between February 14 and 19, 2025. The first system is forecast to begin affecting the state on February 14–15, followed by a second trough deepening offshore from February 16–17. Snowfall totals over the Sierra Nevada could exceed 60 cm (24 inches), while rainfall totals of 25–50 mm (1–2 inches) are forecast across much of the state during the initial 72-hour period.
An atmospheric river affecting California on February 11, 2026, is forecast to evolve into a cross-country storm moving across the southern U.S. through February 13–14, 2026. Widespread rainfall totals of 25 to 75 mm (1–3 inches), with locally higher amounts, are possible across Texas to Georgia. Heavy snow is ongoing in the Sierra Nevada, with additional accumulations expected in the Wasatch and central Rockies.
