California Faces Unprecedented Winter Storm Threat

As a strong Pacific storm system approaches the California coast, the state is bracing for a multi-day event marked by heavy snowfall, fierce winds, and treacherous travel conditions across the Sierra Nevada region. From Thursday evening through Saturday, residents and travelers alike should prepare for significant weather challenges.

Storm System Predictions

The storm system is expected to intensify as it makes landfall, leading to heavy precipitation. According to forecasts from the Weather Prediction Center (WPC), this will include extensive mountain snow and elevated risks of excessive rainfall particularly along the upslope terrain. The ramifications of this system may extend beyond just snow accumulations, affecting visibility and overall travel safety.

Image credit: NOAA/GOES, Zoom Earth, The Watchers. Acquired at 22:50 UTC on November 12, 2025.

Winter Weather Advisories Issued

The National Weather Service (NWS) office in Las Vegas has issued a Winter Weather Advisory for the Eastern Sierra Slopes starting at 19:00 PST on Thursday through 10:00 PST on Friday. Anticipated snowfall includes:

• Up to 10 cm (4 inches) at elevations between 2,600 and 2,900 meters (8,500–9,500 feet)
• 10–30 cm (4–12 inches) accessible at elevations above 2,900 meters (9,500 feet).

As per forecasts, wind gusts may reach 80 km/h (50 mph), resulting in reduced visibility and hazardous travel conditions, particularly near Aspendell along Highway 168.

Northward, the NWS Reno office has issued a similar advisory for the Greater Lake Tahoe Area from 22:00 PST on Thursday to 12:00 PST on Friday, highlighting:

• Up to 10 cm (4 inches) of snow above 2,400 meters (8,000 feet).
• 5 cm (2 inches) accumulation between 2,300 and 2,400 meters (7,500–8,000 feet).

Severe Wind Impacts

Wind gusts in the Sierra ridge could escalate to 95 km/h (60 mph), impacting the Friday morning commute and potentially causing tree and power line damage. Wave heights on Lake Tahoe may also reach up to 0.6 meters (2 feet), further complicating conditions.

Image credit: CW3E.

Snowfall Expectations for the Northern Sierra Nevada

Another advisory has been issued by the NWS Sacramento office for the West Slope Northern Sierra Nevada above 2,100 meters (7,000 feet), effective from 16:00 PST Thursday to 07:00 PST Friday. Snow forecasts include:

• 7–20 cm (3–8 inches) south of Highway 50
• 30–45 cm (12–18 inches) on higher peaks.

Snow levels are predicted to drop from 2,400 meters (8,000 feet) to around 2,000–2,300 meters (6,500–7,500 feet) late Thursday night into Friday.

Risk of Flash Flooding

With widespread coastal rainfall expected today, areas in the Bay Area and Sierra upslope regions face a slight risk of excessive rainfall, which may lead to localized flash flooding.

On Friday, scattered showers and thunderstorms are projected to shift southward into southern California, with a similar risk of excessive rainfall impacting northern Los Angeles County and the Transverse Ranges.

Ongoing Alerts for Strong Winds

High Wind Warnings and Wind Advisories are currently in place across various regions of northern and central California, along with western Nevada. These strong winds will coincide with ongoing heavy snowfall, which is likely to cause travel disruptions and delays in major mountain corridors.

Summary

As California prepares for this powerful winter storm, it’s essential for residents and visitors to stay informed about conditions and heed advisories from local weather officials. The combination of heavy snowfall, wind gusts, and potential flooding makes this a significant weather event to monitor closely.

For further details, visit the NWS Weather Prediction Center for the latest updates on storm developments and warnings.