California is facing a volatile week of weather as a potent winter pattern brings the rare combination of flooding rain, heavy mountain snow and strong winds from the far north of the state to the Mexican border. Forecasters warn that the multi-day barrage will snarl travel on highways and in the air, threaten power lines and trigger flash flooding and debris flows in vulnerable communities.
Back-to-Back Storms Target the State
Meteorologists with the National Weather Service say California is entering a stretch of back-to-back Pacific storms that will sweep across the state through at least Thursday, February 19. The first system began spreading rain into Northern California late Sunday, with a colder, more vigorous storm following quickly on its heels from Tuesday into midweek.
In the Sacramento and San Joaquin valleys, forecasters have designated Monday and Tuesday as high-impact days, with the first storm delivering the bulk of the lowland rainfall and the second system dragging snow levels sharply lower. Forecast guidance indicates 1 to 2 inches of rain for many valley locations, with locally higher totals in the foothills and coastal ranges.
Farther south, from the Central Coast into Los Angeles, Orange and San Diego counties, periods of rain, gusty winds and isolated thunderstorms are expected through at least Thursday. The unsettled pattern is being fueled by a persistent jet stream aimed at the West Coast and pockets of subtropical moisture that periodically enhance rainfall rates along the storm track.
Flood Watches and Urban Inundation Fears
Hydrologists are most concerned about the potential for flooding in low-lying urban areas, smaller streams and along road corridors that are prone to poor drainage. With multiple days of showers and downpours on tap, soils are expected to quickly become saturated, allowing subsequent bursts of rainfall to run off more efficiently into creeks, storm drains and rivers.
In Northern California, local flood advisories are expected where bands of heavier rain set up over foothill terrain and burn scar regions. Even away from major waterways, forecasters warn that repeated downpours may overwhelm storm drains, leading to ponding on freeways and surface streets during the morning and evening commutes.
In Southern California, flood watches have been issued for portions of coastal and valley communities as well as inland foothill zones. Emergency officials are reiterating a familiar message to residents who live near recent wildfire burn scars: heavy, short-duration rain can rapidly trigger debris flows that behave more like wet concrete than water, carrying rocks, mud and vegetation downslope with little warning.
With the storm series expected to bring multiple rounds of precipitation, public safety agencies are cautioning drivers never to attempt to cross flooded roads, noting that even a foot of fast-moving water can be powerful enough to sweep away vehicles.
Sierra and Southern California Mountains Brace for Feet of Snow
While lower elevations contend with drenching rain, the Sierra Nevada and other high ranges are bracing for some of the most significant mountain snowfall of the season. A winter storm warning is in effect for large portions of the central Sierra through Wednesday night, with totals of several feet expected at the higher passes.
In the central Sierra zones overseen by the National Weather Service office in Hanford, forecasters say storm totals could approach 8 feet at the highest peaks, with wind gusts up to 60 miles per hour on exposed ridges. Snow levels, initially around 5,500 to 6,000 feet, are expected to sink to roughly 4,000 feet by Tuesday morning and may briefly dip near 3,000 feet as the colder second storm arrives.
To the north around Donner Pass and the Tahoe Basin, forecast models indicate the potential for 3 to 7 feet of snow by Wednesday, creating whiteout conditions at times on Interstate 80 and Highway 50. Chain controls were already in place Monday morning on long stretches of both corridors as heavy snow began to blanket the pavement.
Southern California’s tallest peaks will not be spared. In San Diego County, the National Weather Service expects widespread heavy snow above about 6,000 feet through Thursday, with snow levels possibly settling near 3,500 to 4,000 feet late Wednesday into early Thursday. Similar low snow levels are forecast for the San Bernardino and Riverside County mountains, raising the possibility of light accumulations on high desert routes and passes that more often see rain than snow.
Damaging Winds Threaten Power and Air Travel
Strong and, at times, damaging winds are another key component of this week’s storm pattern. Ahead of the cold fronts, southerly winds are expected to ramp up across much of Northern California, with gusts to around 45 miles per hour in the Sacramento Valley and 50 miles per hour or higher along Sierra ridge tops and in wind-prone gaps.
These winds are already having ripple effects on transportation. In the San Francisco Bay Area, powerful gusts Sunday night and early Monday led to significant delays at San Francisco International Airport, where a ground delay program pushed average arrival holdups beyond four hours and forced more than a dozen cancellations. Airborne flights approaching the region were also slowed, and officials warned of additional interruptions as the week’s second and third waves of storminess arrive.
Farther south, the storm will shift the focus to strong south to west winds from the beaches to the deserts. Forecasters in San Diego County expect the most intense winds along mountain crests and adjacent desert slopes from late Tuesday into Wednesday, with the potential for localized wind damage, blowing dust and reduced visibility on east-west routes such as Interstate 8.
Gusts in the 30 to 50 mile per hour range could topple tree branches and power lines in many communities, particularly where soils have been loosened by days of steady rainfall. Utilities are preparing for scattered outages and urging customers to secure outdoor furniture and other loose objects that could become windblown debris.
Highways, Mountain Passes and Commuter Routes Under Strain
From the Sierra passes to coastal freeways, transportation agencies are preparing for a week of difficult travel. Caltrans crews have already begun 24-hour operations in several mountain districts, using plows, blowers and graders to keep key corridors open as snowfall intensifies and winds whip up ground blizzards near summits.
On Interstate 80, chain controls and reduced speed limits are expected to be a near-constant feature between Colfax and Truckee through at least Wednesday, with the potential for full closures if traffic accidents or avalanche concerns arise. Highway 50 over Echo Summit is facing a similar outlook, and drivers heading toward South Lake Tahoe are being urged to delay nonessential travel until conditions improve later in the week.
Lower elevation routes will face their own challenges. In the Central Valley, drivers can expect bouts of heavy rain that sharply cut visibility, along with standing water on shoulders and in the ruts of heavily traveled lanes. In and around the Bay Area, major arteries are vulnerable to flooding where leaves and debris clog storm drains, and wind-blown tree limbs may block lanes or knock out traffic signals.
In Southern California, forecasters say hazardous driving conditions are likely at times on coastal freeways and canyon roads, where wind-whipped downpours could lead to hydroplaning and rockfall in steep terrain. The combination of slick pavement, gusty crosswinds and occasional thunderstorms may create prolonged delays during peak commuting hours.
Airlines, Rail and Transit Prepare for Disruptions
While the worst travel effects will hit roads and mountain passes, the state’s broader transportation network is also bracing for weather-related turbulence. Airlines are warning passengers of potential delays and cancelations at major hubs including San Francisco, Oakland, Sacramento, Los Angeles and San Diego as the storms progress south and east.
Carriers typically slow arrivals and departures during periods of low cloud ceilings, heavy rain or crosswinds that exceed safe operating thresholds. With the jet stream riding directly over California for much of the week, pilots may also encounter significant turbulence on approach and departure routes, prompting air traffic controllers to space aircraft farther apart and adding to delays.
Intercity rail services, including key Amtrak routes through the Central Valley and along the coast, can also be impacted when saturated soils lead to minor landslides or debris on tracks, or when strong winds damage overhead lines and signals. Local transit agencies are preparing for detours and slower service if flooded intersections, downed trees or power outages disrupt regular routes.
Officials advise travelers to build flexibility into their plans, check conditions frequently and monitor alerts from airlines, rail operators and local transit providers before heading out. Allowing extra time to reach airports and stations will be particularly important during the midweek peak of the storm sequence.
Emergency Preparations Ramp Up Across California
State and local emergency managers are using lessons learned from previous atmospheric river events to get ahead of the impacts. The California Office of Emergency Services has been coordinating with county agencies, fire departments and utility companies to pre-position swift-water rescue teams, high-clearance vehicles and extra personnel in areas expected to be hardest hit by flooding and snow.
In communities that have experienced mudslides and debris flows in recent years, authorities are reinforcing or clearing existing catch basins and drainage channels, and in some cases are staging sandbags and temporary barriers. Residents who live near steep slopes or at the mouths of canyons have been urged to review evacuation routes and stay alert for changing conditions, particularly during overnight hours when intense rain bands can move through quickly.
Public information campaigns are focusing on straightforward safety actions. Officials are reminding residents to clear gutters and yard drains where it is safe to do so, charge phones and backup batteries in case of power outages, and assemble basic emergency kits that include flashlights, extra medications and nonperishable food.
In the mountains, forecasters are urging anyone considering travel to pack extra clothing, food and water, and to ensure vehicles are equipped with snow chains and full fuel tanks. Those who can postpone trips over the Sierra or into higher Southern California passes until conditions stabilize are being strongly encouraged to do so.
Stormy Week Points to Larger Climate Concerns
Beyond the immediate hazards, this week’s turbulent weather adds to a growing pattern of intense, fast-hitting storms that have defined recent California winters. While storms are nothing new to the state’s climate, researchers say there is mounting evidence that warming oceans and atmosphere are helping to supercharge some systems, leading to heavier downpours and more dramatic swings between dry and wet periods.
The current series of storms will help replenish mountain snowpack and boost reservoir levels that feed much of the state’s water supply. Yet experts caution that relying on a few powerful events each winter is a precarious way to manage a water system built around the expectation of gradual, sustained snowmelt. Heavy rain falling on snow can also accelerate runoff and heighten flood risks downstream.
For travelers and residents, the immediate concern is navigating the coming days safely. With heavy rain at lower elevations, blizzard conditions in the high country and disruptive winds across a wide swath of the state, Californians are being urged to take forecasts seriously, stay informed through trusted local outlets and adjust their plans accordingly as the turbulent week unfolds.