A powerful winter storm is sweeping across California’s Sierra Nevada this week, bringing heavy snowfall, strong winds, and dangerous travel conditions to some of the state’s most iconic mountain landscapes. Winter weather alerts are in effect for Yosemite National Park and surrounding high country, as well as Mono and Lassen counties, where forecasters warn of rapidly deteriorating road conditions, whiteout visibility at times, and the potential for downed trees and power lines. For travelers heading to the mountains for winter recreation or trying to cross key passes, the next several days will require flexibility, preparation, and close attention to the latest advisories.
Current Storm Setup Across the Sierra Nevada
The present system is the first in what forecasters say will be a more active mid-February pattern after weeks of unusually dry, mild weather in much of the West. A cold upper-level low is sliding southeast into California, tapping Pacific moisture and turning it into widespread mountain snow. The strongest impacts are focused along the spine of the Sierra Nevada, from Yosemite’s high elevations north toward Lassen Volcanic National Park and the higher terrain of far northeastern California.
For travelers, this means changing conditions almost by the hour. Snow levels are generally starting around 6,000 to 6,500 feet, then dropping overnight toward 5,000 feet or even lower in some interior valleys. That puts many popular passes, resort access roads, and forest highways squarely in the zone for accumulating snow and icy pavement. As colder air deepens, snow will stick more efficiently, and even short bursts of heavy showers can quickly coat roadways.
This storm is also accompanied by significant winds along the crests and exposed ridges. Gusts across the highest elevations are projected to reach 50 to 70 miles per hour at times, increasing the risk of drifting snow, blowing snow, and sudden whiteouts, particularly along east-west corridors that cross the Sierra crest. Even during lulls in snowfall, these winds can keep visibility low and make driving treacherous.
Winter Storm Warnings for Yosemite and the Central Sierra
Yosemite National Park and its surrounding high country are under a Winter Storm Warning through the middle of the week, with conditions expected to worsen from late Monday night through Wednesday. The warning encompasses higher elevations of the park, including Tioga Road and the upper reaches of the Yosemite high country that are already snow covered, but it will also affect approaches from the west and south where travelers begin to climb into the Sierra.
Forecasters are calling for widespread snow accumulations of 12 to 18 inches above roughly 7,000 feet, with localized totals up to 24 inches on the highest ridges and peaks. The heaviest bands are expected from late Tuesday into early Wednesday, when near-continuous snowfall and gusty winds may reduce visibility to near zero at times. Even lower-elevation park roads can see slick conditions as temperatures drop overnight and slush refreezes into ice.
In addition to snow, wind gusts over ridgetops could reach or exceed 50 miles per hour, particularly along exposed passes and open valley approaches. This will increase the risk of falling branches and sporadic power outages in gateway communities, as well as produce hazardous wind chills for anyone hiking, camping, or driving in remote areas. Visitors should expect rapid changes in conditions and check with park authorities before setting out for any backcountry excursions.
Travel Impacts in Mono County and the Eastern Sierra
On the eastern slope of the Sierra, Mono County is facing especially challenging travel conditions as the storm pushes across the crest and spills into the high desert. A Winter Weather Advisory is in effect for much of the county, including key travel corridors such as Highway 395 from June Lake to Mammoth Lakes and north toward Bridgeport and Lee Vining. While this advisory indicates slightly lower snow totals than in the highest central Sierra, it still represents a serious threat to safe travel.
Forecasts call for 4 to 8 inches of snow along and just west of Highway 395 from June Lake to Mammoth Lakes, with 6 to 12 inches and locally more along the Sierra crest above 8,000 feet. Farther north along Highway 395, around Bridgeport and Lee Vining, even a couple of inches will be enough to create slick, icy conditions and intermittent chain requirements. Winds in the upper elevations may gust to 70 miles per hour, which can send snow streaming across the highway and create sudden, localized whiteouts.
The combination of accumulating snow, gusty winds, and low temperatures will continue through at least Wednesday afternoon. Drivers in Mono County should expect rapidly changing controls, including the possibility of chain checkpoints, reduced speed limits, and spot closures if conditions deteriorate faster than expected. Those heading toward popular winter destinations like Mammoth Lakes should allow for significant extra time and be prepared for delays.
Lassen County and Northern Sierra Updates
Farther north, Lassen County and surrounding high terrain in northern California are also under winter weather alerts as this system pushes into the region. The county includes a mix of higher-elevation forest, volcanic peaks, and more open, windswept terrain, all of which respond differently to heavy, wind-driven snow. Even where snow totals are somewhat lower than in the central Sierra, strong winds can have an outsized impact by blowing snow across open roadways and reducing visibility.
Travelers heading toward Lassen Volcanic National Park and nearby recreation areas should be prepared for complex conditions. Many high-elevation park roads are seasonally closed, but access routes, secondary forest roads, and local connectors can still be impacted by accumulating snow, patchy ice, and drifts. As the storm intensifies, localized bands of heavier snow may set up, creating a sharp contrast between relatively clear stretches and short but hazardous segments of road.
Local authorities in northern Sierra and Cascade foothill communities are urging visitors to monitor county and state updates closely. Plow crews and maintenance staff will be out throughout the event, but snowfall rates can periodically outpace their efforts, especially overnight or during peak storm periods. Expect slower travel, potential one-lane controls, and the possibility that side roads may not be cleared as frequently as main highways.
Road Conditions, Chain Controls, and Closures
Highway travel across the Sierra Nevada is expected to be significantly impacted. Mountain passes such as Interstate 80 over Donner Summit and U.S. 50 over Echo Summit regularly experience snow and chain controls during storms, and this system is no exception. As snow levels fall and accumulations build, state transportation crews are likely to implement chain requirements for most vehicles, with exemptions only for four-wheel-drive vehicles equipped with approved snow tires when conditions allow.
Chain checkpoints can appear quickly at major bottlenecks, and delays are common when a surge of drivers reaches these areas unprepared. Motorists who do not carry chains or other approved traction devices may be turned around, adding hours to their trips or forcing overnight stops in gateway communities. Slow-moving traffic, spinouts, and minor collisions are frequently reported during intense snow periods, further backing up already congested routes.
Secondary highways and local mountain roads, including access routes to ski resorts, trailheads, and cabin communities, may see intermittent closures or strict controls. In some cases, authorities may restrict travel to residents and essential services only when conditions become too hazardous. Travelers should not depend on navigation apps alone, as they may suggest alternate routes on lightly maintained or unplowed roads that are unsafe during storm conditions.
What Travelers Should Do Now
With winter storm and snow advisories already in effect, anyone planning to visit Yosemite, Mono County, Lassen County, or the broader Sierra Nevada region over the coming days should reassess their itinerary. Non-essential travel during the height of the storm is discouraged, and delaying a trip until after the main snow bands have passed can significantly reduce risk. If travel is unavoidable, planning ahead is critical.
Authorities strongly advise carrying a full tank of fuel or a full battery charge, since delays, detours, or unexpected closures can add many hours to a journey. Emergency supplies in the vehicle remain essential, including warm clothing, blankets, food, water, an ice scraper, shovel, and a flashlight. Snow chains or other traction devices should be sized correctly for your tires and inspected before departure, and drivers should know how to install them safely away from traffic.
Travelers should also monitor weather forecasts and road condition updates multiple times per day, as timing and intensity projections can shift as the storm evolves. Conditions can differ dramatically between lower valleys and high passes, so a clear drive at the start of your trip does not guarantee easy conditions later on. Calling ahead to accommodations, ski resorts, or park services can help avoid surprises and confirm whether facilities are open or operating on reduced schedules.
Storm Timing and What Comes Next
The most intense period of snowfall and wind for much of the Sierra Nevada is expected from late Tuesday through Wednesday, with gradual improvement in conditions afterward as the system exits to the east. However, lingering snow showers, icy roads, and residual chain controls are likely to persist beyond the official end times of current warnings and advisories. Travelers should not assume a rapid return to dry pavement immediately after the heaviest snow has passed.
Looking ahead, meteorologists are tracking additional systems that could follow this storm into mid-February, including the potential for a stronger, colder event around the Valentine’s Day weekend. While details remain subject to change, the broader pattern shift suggests that the Sierra Nevada may be headed into a more active stretch, with multiple opportunities for significant snowfall. This may help improve the regional snowpack after a historically low start to the year, but it will also prolong periods of difficult travel.
For winter travelers, that means a continued need for flexibility in planning, backup dates when possible, and a willingness to call off or reroute trips if conditions deteriorate. Checking forecasts several days in advance, then again 24 hours before departure and on the day of travel, will remain an essential habit through the remainder of the month.
Balancing Winter Adventure With Safety
Despite the hazards, winter storms like this one also bring opportunities. For ski resorts, snowshoers, backcountry skiers, and photographers, fresh snowfall transforms Yosemite’s granite cliffs, Mono County’s alpine lakes, and Lassen’s volcanic peaks into dramatic winter scenes. Once the storm clears and avalanche and road risks are reassessed, these landscapes will offer some of the best winter conditions so far this season.
However, the line between adventure and danger can be thin during and immediately after major storms. Backcountry users should be especially cautious, checking avalanche forecasts, traveling with proper safety gear, and never venturing into remote terrain alone. Within national parks and forests, staying on open, designated trails and respecting closures helps protect both visitors and rescue personnel.
Ultimately, the key message from forecasters and local authorities is to prepare, adapt, and respect the power of Sierra Nevada winter weather. This week’s storm is a reminder that conditions in California’s mountains can change rapidly, turning a routine drive or day hike into a serious challenge. With thoughtful planning, flexible itineraries, and close attention to the latest updates, travelers can stay safe while still experiencing the extraordinary winter beauty of Yosemite, Mono, and Lassen counties as the snow returns to the high country.