A massive weather system combining a bomb cyclone and atmospheric river is poised to unleash devastating conditions across the U.S. West Coast.
According to Daily Mail, the National Weather Service has issued alerts for northern California, Oregon, and Washington as the regions prepare for hurricane-force winds, severe flooding, and substantial snowfall beginning Tuesday afternoon.
The unprecedented weather event is expected to generate wind gusts reaching 70 miles per hour along coastal areas from Eureka to Coos Bay and north of Aberdeen. Inland cities, including Oregon's Klamath Falls, Bend, and Pendleton, along with Seattle, Washington, are forecasted to experience winds between 50 to 60 miles per hour.
The bomb cyclone's rapid intensification is particularly noteworthy, with pressure dropping almost 70 millibars within 24 hours – a rate comparable to Category 4 hurricane conditions. This dramatic pressure drop significantly exceeds the standard 24-millibar threshold typically required for bomb cyclone classification. The system's intensity rivals that of Hurricane Milton, which experienced an 84-millibar pressure loss during its transformation from Category 1 to Category 5.
Meteorologist Ryan Maue predicts the combination of the bomb cyclone and atmospheric river will deliver nearly 20 trillion gallons of rainfall across the Northwest this week. The precipitation forecast shows potential accumulations of up to five inches across north-central and northwestern California, western Oregon, and western Washington, with northeastern California possibly receiving up to 20 inches.
The timing of the storm's progression indicates the atmospheric river will initially target southwestern Oregon and Northern California's coasts Tuesday night through Wednesday. As the week progresses, the system is expected to shift southward, potentially affecting central and Southern California by the weekend.
Power outages are anticipated across all three affected states, particularly in areas under high-wind warnings. The combination of saturated soil and powerful winds creates hazardous conditions for power infrastructure and increases the risk of falling trees.
AccuWeather Senior Meteorologist Heather Zehr described the storm's impact on the San Francisco area:
Soaking rain from the storm will reach the San Francisco Bay area but not until later in the week. The heaviest rain will fall near and north of the North Bay and up along the coast of Northern California while San Francisco and the South Bay will be in the zone where rainfall will diminish quickly from north to south.
The storm's reach extends beyond the immediate coastal regions, with Idaho expecting three to four inches of rainfall. Areas as distant as Kansas and the California-Mexico border could receive up to an inch of precipitation.
Communities affected by recent wildfires face heightened risk during this weather event. According to NOAA, burn scars create conditions where the soil becomes as water-repellant as pavement, significantly increasing the likelihood of flooding, mudslides, and rockslides in these vulnerable areas.
The heavy precipitation will be accompanied by significant snowfall, with several inches to a foot expected over mountain passes in the Cascades. This mixed precipitation pattern adds another layer of complexity to the already challenging weather conditions.
The current forecast positions the most severe storm conditions between Vancouver Island in Canada and the Oregon-California border on Tuesday night, with a gradual southward progression expected through midweek.
The approaching weather system represents one of the most significant meteorological events to impact the West Coast this season. The combination of a rapidly intensifying bomb cyclone and Category 5 atmospheric river will bring hurricane-force winds, extensive flooding, and heavy mountain snow to California, Oregon, and Washington through the remainder of the week, with effects potentially lingering into the weekend.
