Tracking Weather Extremes: December 2025 Pacific Northwest Flooding

This visualization uses NASA's GEOS-FP data to illustrate the December 2025 atmospheric river that brought extreme precipitation to the Pacific Northwest. The analysis displays two key components: the total precipitable water carried by the atmospheric river as it transported moisture from the Pacific Ocean, and the resulting cumulative precipitation that fell across Washington, Oregon, British Columbia, and Montana beginning December 8, 2025. This powerful atmospheric river system delivered up to 10 inches of rain in some areas and an estimated 5 trillion gallons of water over one week. The data reveals how moisture from the Pacific was channeled inland by this Category 5 atmospheric river, creating the meteorological conditions that led to widespread flooding across the region. The extreme precipitation broke multiple records and triggered catastrophic flooding that forced over 100,000 people to evacuate in Washington, with states of emergency declared in both Washington and British Columbia.