• Winter Weather Advisories issued as Sierra Nevada prepares for heavy snow

    A strengthening low-pressure system offshore is forecast to spread heavy precipitation and mountain snow across the Sierra Nevada from Thursday, November 13 through November 15, 2025. Winter Weather Advisories are in effect for the Eastern Sierra Slopes, Greater Lake Tahoe Area and the West Slope Northern Sierra Nevada, with snow levels forecast to drop into November 14 and accumulations reaching 30–60 cm (12–18 inches) at the highest peaks.

  • Flood Watch and marine Storm and Gale Warnings in effect for Mendocino and Lake counties region, California

    Interior Mendocino and Lake counties are under a Flood Watch from late Wednesday, November 12, through Thursday morning, November 13, 2025, as 50–75 mm (2–3 inches) of rain is forecast within several hours. Marine Storm and Gale Warnings are also in effect offshore, where winds up to 95 km/h (60 mph) and seas up to 8 m (27 feet) are expected.

  • Earthquake swarm in progress along Calaveras fault near San Francisco, California

    Over 40 earthquakes were recorded along the Calaveras fault southeast of San Ramon, California, between November 9 and 10, 2025. The largest event, M3.8, occurred at 09:38 LT (17:38 UTC) on November 9 at a depth of 9.2 km (5.7 miles). Geological and seismic studies show that the Calaveras fault is capable of generating an event in the M6.5 to M7.0 range over long-term timescales.

  • Atmospheric river forecast to bring heavy precipitation to California from November 12 to 15

    A developing low-pressure system over the Northeast Pacific is forecast to direct a strong atmospheric river (AR) toward California between November 12 and 15, 2025. The Center for Western Weather and Water Extremes (CW3E) indicates a high probability of moderate to strong AR conditions in Northern and Central California, with heavy precipitation possible in the Sierra Nevada and coastal ranges.

  • Four atmospheric rivers forecast to bring heavy rainfall across the U.S. West Coast

    Four back-to-back atmospheric rivers are forecast to make landfall along the U.S. West Coast between November 3 and November 9, 2025. Heavy rainfall totals of 76–130 mm (3–5 inches), with isolated amounts up to 177 mm (7 inches), could lead to localized flooding in parts of northern California and Washington State throughout the week.