The strongest part of a series of storms barreled into Northern California on Sunday, bringing flooding, heavy snow and concerns about avalanches.
Officials reported scattered flooding and mudslides throughout the region, including a washed out road in Windsor that required the rescue of two people. Local authorities were watching rising water levels at several key rivers including the Truckee, Merced, American and Russian.
An “extreme” avalanche warning was issued for parts of the Sierra Nevada Mountains Sunday because of heavy snow. In Mammoth Lakes, officials said higher elevations recorded 48 inches of snow in the last two days.
Winds topped 50 mph in some areas. A woman was killed in the East Bay suburb of San Ramon on Saturday when she was struck by a falling tree at a golf course amid heavy winds.
Up to 12 inches of rain is expected to fall on areas below 8,500 feet beginning Saturday morning, and up to 7 feet of snow could bury higher elevations, according to the National Weather Service. Forecasters said the storm was packing the same wallop as one that hit Northern California in 2005, causing $300 million in damage.
“It’s going to be a busy weekend,” said Edan Weishahn, a meteorologist with the National Weather Service in Reno, sighing.
The rain moved in late Friday and continued into Saturday morning, with the most powerful punch expected later in the day.
In the eastern Sierra Nevada, snow continued to fall at higher elevations while rain drizzled lower down as officials warned that wetter, rainier conditions on tap for later this weekend could spell trouble.
Surfer and Huntington Beach lifeguard Jachin Hamborg watches the dramatic sky and waves after surfing following his lifeguarding shift at dusk at the Huntington Beach pier.(Allen J. Schaben / Los Angeles Times)
A man is silhouetted against a dramatic sky at sunset while walking on the Huntington Beach pier.(Allen J. Schaben / Los Angeles Times)
Pedestrians stay dry in the rain on 5th Street in downtown Los Angeles.(Christina House / Christina House)
A pedestrian takes to flight crossing 4th Street in Santa Ana after heavy rain flooded the area.(Allen J. Schaben / Los Angeles Times)
Snowplows clear Highway 18 during a storm on Jan. 12, 2017, in Running Springs.(Gina Ferazzi / Los Angeles Times)
Jessica Pompa and Albert Arroyo make a snowman at Firehouse Park in Running Springs.(Gina Ferazzi / Los Angeles Times)
Michelle Graves keeps an eye on the sky as she waits to cross Spring Street in downtown Los Angeles.(Luis Sinco / Los Angeles Times)
Laurel Canyon Boulevard remained closed in both directions Thursday morning in the Hollywood Hills after part of a home’s concrete foundation tumbled down a hillside after a round of rainfall.(Al Seib / Los Angeles Times)
News crews gather on Laurel Canyon Blvd, which remained closed in both directions Thursday morning in the Hollywood Hills when part of a home’s concrete foundation tumbled down a hillside after a round of rainfall.(Al Seib / Los Angeles Times)
A pedestrian wades through a flooded 4th Street in Santa Ana.(Allen J. Schaben / Los Angeles Times)
Traffic moved slowly on a snowy Highway 18 in the Running Springs area.(Gina Ferazzi / Los Angeles Times)
Members of a film crew shelter under umbrellas as the rain comes down in front of L.A. City Hall.(Luis Sinco / Los Angeles Times)
A pedestrian wades through a flooded 4th Street in Santa Ana carrying her daughter.(Allen J. Schaben / Los Angeles Times)
A man crossing the street gets caught in a heavy burst of rain on 4th Street in Santa Ana.(Allen J. Schaben / Los Angeles Times)
Bruce MacDonnell paddles over a flooded road in Guerneville on Wednesday after the Russian River crested.(Kent Porter / Press Democrat)
A dog swims pass a flooded dinosaur display at Playland Miniature Golf Course in Guerneville on Wednesday.(Kent Porter / Press Democrat)
With Russian River waters rising, Dustin Coupe of Guerneville talks with an operator at a phone booth on River Road. Dozens of Northern California residents have been rescued by boats and firetrucks from flooded homes near Hollister.(Kent Porter / Press Democrat)
A Guernville resident walks down steps toward the foodwater surrounding his home.(Justin Sullivan / Getty Images)
Residents get out of their canoe in front of the Pee Wee Golf and Arcade on Drake Road in Guerneville.(John G. Mabanglo / European Pressphoto Agency)
Residents paddle along River Lands Road in Guerneville.(John G. Mabanglo / European Pressphoto Agency)
The entrance to Stealhead Beach Park in Forestville is closed on Wednesday because of flooding.(John G. Mabanglo / European Pressphoto Agency)
A woman walks through water from a king tide that flooded onto the Embarcadero in San Francisco on Wednesday.(Jeff Chiu / Associated Press)
Caltrans worker Brad Larson is whipped by high winds on Tuesday as he mans a checkpoint closing all northbound traffic at U.S. 395 and State Route 203 near Mammoth Lakes.(Brian van der Brug / Los Angeles Times)
Caltrans worker Mark Reistetter tells a Reno-bound truck driver his options at a checkpoint closing all northbound traffic at U.S. 395 and State Route 203 near Mammoth Lakes.(Brian van der Brug / Los Angeles Times)
More than 100 trucks line Main Street in Lone Pine on Tuesday, stranded as U.S. 395 closed to high-profile vehicles in both directions because of high winds.(Brian van der Brug / Los Angeles Times)
A Mammoth Mountain employee directing traffic is dwarfed by a snow removal vehicle on Minaret Road leading to the Mammoth Mountain ski area in Mammoth Lakes.(Brian van der Brug / Los Angeles Times)
A tow truck driver pulls a pickup truck out of a snowbank in the median of U.S. 395 near Mammoth Lakes.(Brian van der Brug / Los Angeles Times)
Clouds drift over the Owens Valley in a view from above Round Valley near Bishop.(Brian van der Brug / Los Angeles Times)
Emma Soriano jumps in a puddle on the Manhattan Beach Pier after posing for pictures for her dad.(Jay L. Clendenin / Los Angeles Times)
With the Manhattan Beach Pier in the distance, surfers scan the waves of Hermosa Beach.(Jay L. Clendenin / Los Angeles Times)
Morgan Harris of Hermosa Beach rides home along The Strand after a couple of hours of surfing south of Hermosa Beach.(Jay L. Clendenin / Los Angeles Times)
A biker at Hermosa Beach, where people were dealing with a lingering rainstorm.(Jay L. Clendenin / Los Angeles Times)
A break in a series of storms moving across California highlights the snow-covered White Mountains looming over U.S. Highway 395 in Crowley Lake.(Brian van der Brug / Los Angeles Times)
Traffic moves slowly at the Donner Pass Road exit on snowy Interstate 80 in Soda Springs.(Gary Coronado / Los Angeles Times)
The Green Church, a beloved landmark along U.S. 395, is partly obscured by snow during a break in a series of storms in the Eastern Sierra Nevada near Mammoth Lakes.(Brian van der Brug / Los Angeles Times)
Snow falls along Interstate 80 at Exit 184 in Truckee.(Gary Coronado / Los Angeles Times)
A break in a series of storms in the Eastern Sierra Nevada highlights the snow-covered White Mountains near Convict Lake.(Brian van der Brug / Los Angeles Times)
A plow removes freshly fallen snow along Donner Pass Road in Soda Springs, Calif.(Gary Coronado / Los Angeles Times)
On a snowy day, a sign makes it clear that chains are required on this stretch of Interstate 80 in Truckee.
(Gary Coronado / Los Angeles Times)
Jack Ryan and his family came out to see firsthand water cresting the south bank of the American River, flooding American River Parkway in Sacramento’s Discovery Park.(Gary Coronado / Los Angeles Times)
Folsom Lake continues to rise as the Folsom reservoir releases water into the American River.(Gary Coronado / Los Angeles Times)
Traffic is backed up while CalTrans removes falling rocks and mud which closed one westbound lane along Interstate 80 east of Truckee, near Floriston, Calif.(Gary Coronado / Los Angeles Times)
Wendy Payne of CalTrans clears debris along Highway 89 near Truckee.(Gary Coronado / Los Angeles Times)
Park Ranger Cullen Tucker walks across a bridge during a rain storm on the Merced River in Yosemite National Park.(Gary Kazanjian / Associated Press)
Mammoth Mountain ski patrolman Cliff Klock, left, and Forest Service member Jeff Karl fire a 105-millimeter howitzer on Sunday to mitigate avalanche paths at the top of the ski area in Mammoth Lakes, Calif.(Brian van der Brug / Los Angeles Times)
Mammoth Mountain ski patrolman Cliff Klock prepares to load a 105-millimeter shell into the breach of a 1943 howitzer.(Brian van der Brug / Los Angeles Times)
Mammoth Mountain ski patrol clear avalanche chutes on Sunday morning after a night of snow.(Brian van der Brug)
A CHP officer proclaims “aw man!” as he is photographed after becoming stuck in heavy snow in the median of US 395 near Crowley Lake as snow falls on the Eastern Sierra Nevada.(Brian van der Brug / Los Angeles Times)
Monique Long hauls sandbags from her SUV to make a barrier to divert the rain and melting snow from flooding her garage, while her friend Jenna Shropshire, right, helps shovel snow, in Truckee, Calif.(Gary Coronado / Los Angeles Times)
Mitch Brown operates a skid steer removing snow so water can flow freely preventing flooding in Soda Springs, Calif.(Gary Coronado / Los Angeles Times)
Skiers coming off the mountain endured rainy conditions all day at the Sugar Bowl Ski Resort, in Norden, Calif.(Gary Coronado / Los Angeles Times)
The train passes under an avalanche tunnel near the Sugar Bowl Ski Resort, in Norden, Calif., on Jan. 7, 2017.(Gary Coronado / Los Angeles Times)
Caltrans snowplows clear heavy snow from the northbound lanes oh highway 395 as snow falls on the Eastern Sierra near Sherwin Summit, Calif.(Brian van der Brug / Los Angeles Times)
Actor Max Baer Jr., left, talks with emergency responders after flipping over his SUV in white-out conditions while traveling northbound on U.S. 395 near Crowley Lake as heavy snow falls on the Eastern Sierra Nevada, Calif. The star of The Beverly Hillbillies said his was not injured.(Brian van der Brug / Los Angeles Times)
A snowcat moves snow in near whiteout conditions on the slopes at Mammoth Mountain.(Brian van der Brug / Los Angeles Times)
A CHP officer maintains a checkpoint to ensure vehicles are compliant with R2 chain restrictions on the northbound 395 just north of Bishop as snow falls on the Eastern Sierra Nevada.(Brian van der Brug / Los Angeles Times)
Caltrans crews have a road-flooded sign in case of heavy rain and snow near the Eastern Sierra Nevada town of June Lake, Calif.(Brian van der Brug / Los Angeles Times)
Caltrans avalanche crew members Sky Greytak, right, and Pat Brannen, left, prepare to set off explosive charges remotely from a laptop during avalanche control operations near the Eastern Sierra Nevada town.(Brian van der Brug / Los Angeles Times)
Caltrans snowplow operator Mike Morgan prepares to turn his plow around after making loops on the 395 between Bishop and Tom’s Place, a route he drives 12 hours a day clearing heavy snow in the Eastern Sierra.(Brian van der Brug / Los Angeles Times)
Mammoth Mountain employees clear paths as snow falls lightly Saturday morning.(Brian van der Brug / Los Angeles Times)
A car spun out and off the road just outside Bishop in sloppy road conditions as the snowfall level fell below 5000.(Brian van der Brug / Los Angeles Times)
California Highway Patrol has established a chain checkpoint near Bishop.(Brian van der Brug / Los Angeles Times)
Chris Guyot, 13, Kayleigh, 10, and their mom, Tricia, and the rest of the family, Evan Guyot, and Tyler, 19, (not pictured) of Orange, Calif., pack up their belongings after being told to evacuate the Yosemite Valley Lodge, in Yosemite National Park. A massive storm bearing down on Central California could overflow rivers, trigger rockslides and topple trees, prompting rangers at Yosemite National Park to close roads to the valley floor.(Michael Macor / San Francisco Chronicle)
Snow covers vehicles in a parking lot in Mammoth Lakes.(Brian van der Brug / Los Angeles Times)
Jorge Gaydam digs out his truck in a parking lot.(Brian van der Brug / Los Angeles Times)
Snow blankets the Sierra Nevada crest north of Bishop along U.S. Highway 395 in Round Valley.(Brian van der Brug / Los Angeles Times)
A plow removes snow from state Highway 203 in Mammoth Lakes.(Brian van der Brug / Los Angeles Times)
Officials toiling to keep highways clear said they were concerned about a warmer phase of the storm that could fall as rain even at higher elevations, melting the built-up snow and unleashing mudslides, flooding and avalanches.
“It’s the rain over the snow that we’re worried about,” said Greg Miller, a Caltrans maintenance manager. “We’ve had snow since Christmas, but now with the warmer trend, we’re worried about water.”
With storm drains frozen, he said, an influx of rain could send water and mud into roadways.
Miller said crews were taking special precautions to prevent rockslides from a segment of U.S. 395 near Lee Vining and avalanches from several other critical transportation corridors.
Friday morning, Caltrans closed part of California 120 near June Lake while a crew set out off remotely detonated charges to clear avalanche-prone slopes of accumulating snow.
Crews were plowing, sanding and blowing snow from roadways around the clock in 12-hour shifts, Miller said.
The California Highway Patrol responded to several reports of rolled-over vehicles and other snow-related collisions on U.S. 395.
Tire chain restrictions were in effect across much of the Sierra Nevada.
Residents in Mammoth Lakes are concerned that warm rain and slush will dam up behind banks of shoveled snow piled high in empty lots and along roads throughout town, then flow wherever it can find a path, clogging existing drainage systems with debris and ice.
“In this town, we don’t even have rain gutters because they get ripped down by snow,” said Lisa Isaacs, a resident and environmental activist. “So, we’re very worried that this storm will flood homes and garages.”
The National Weather Service issued a flood watch warning for Sunday, and town officials advised residents to stock up on water, food, first aid supplies, clothing and bedding, tools and emergency supplies, along with special items for medical conditions.
On a winter war footing, Mammoth Lakes residents lined up throughout the day on Saturday at the town’s utility yard to load up on 40-pound sandbags they hoped would steer waves of slush away from homes, ground-floor condominiums and businesses.
Among them were Mammoth Lakes residents Greg Newbry, 66, a recently retired Mono County employee, and his wife, Linda Salcido, 67, Mono County’s director of public health.
“I was here in 1982 when this town was wrecked by massive flooding,” Newbry recalled. “Main Street was under 2 feet of water. Businesses closed. The roofs of five mobile homes collapsed under the weight of rain on snow.
“If we get all the rain predicted in the forecasts,” he added, “every slab of concrete at ground level is vulnerable, and we live in a ground-floor condominium.”
As she helped tote 20 sandbags to their vehicle, Salcido said she was concerned about the potential effects of flooding countywide.
“Snow, even lots and lots of it, we can handle,” she said. “But a major flood event would lead to countless challenges.”
Rising 11,000 feet from a gap in the Sierra Nevada range, Mammoth Mountain’s steep chutes stand in the path of freshly brewed atmospheric river systems. With relatively low mountains to the west of it, Mammoth receives most of their unspent snow.
But big snowfall, high winds, warm rain and rising temperatures are forces that transform pile powder into unstable clumps that set off avalanches. So Mammoth Mountain Resort specialists were bringing snowpacks down with artillery including howitzers.
Down in Mammoth Lakes, Isaacs spent Saturday hoping that “the rain they keep talking about will turn out to be snow.”
“But it’ll probably be like having a giant fire big hose turned on us and we’ll be swamped,” she said with a nervous laugh. “I just hope that my little $150 water pump can keep with it.”
Mammoth Mountain Chief Executive Rusty Gregory had few answers. “The main topic of conversation over cocktails on Sunday night,” he mused, “will be about what actually happened.”
As snow and rain continued to fall over the Sierra Nevada, highway patrols and maintenance crews were kept busy Friday responding to snow-related accidents and icy road conditions.
Steve Coons operated a massive Caltrans wing plow. Its engine strained as it worked in tandem with another truck to clear and sand two northbound lanes of U.S. 395 north of Bishop, a key transportation corridor along the Eastern Sierra Nevada.
From behind the wheel of the rumbling truck, Coons can feel the weight of the heavy, wet snow as it pushes against the plow blade and is shoved to the side of the highway.
“The truck is really chugging,” he said. “It’s going to be a long day.”
Coons monitors closely the consistency of the snow, which wavers between soft, large flakes and icy shards. The more that falls as rain and ice, the more he worries it will make the roads slick and cause serious trouble for drivers.
“As soon as it gets cold all this ices up,” Coons said. “Not good.”
He and other plow operators are on the roads 24 hours a day, working 12-hour shifts. They will have no shortage of snow to clear with the series of storm cells expected to continue dumping moisture over the area for days.
“Our guys have pretty much been on since Christmas, and it’s not letting up,” said Greg Miller, maintenance manager for Caltrans District 9, which includes Inyo, Mono and eastern Kern counties.
The storm was also bringing wind gusts that topped 50 mph. Officials said they were low snow and icy conditions on Interstate 5 and 80 as well as U.S. 50 and some mountain highways.
The National Weather Service on Saturday released a new timeline for the storms moving through the region:
Saturday: Moderate to heavy snow in mountain areas.
Sunday: Heaviest rain and snow, with risks of flooding.
Monday: Showers and snow continue, with continued flood risk.
Tuesday: New storm moves in, lower snow levels, flood risk.
Wednesday: Showers and snow, with rivers running high.
“We’re expecting heavy, heavy rain. It starts out as snow then turns to rain then turns to snow again,” Hammitt said. “We’re concerned about the melt increasing waterways and all the lakes.”
Hammitt recalled storms in 1997 and 2005 when runoff overwhelmed local rivers and creeks and sent water into roads and homes, lifting some buildings off their foundations.
“We have streams, creeks, rivers. We have lakes and ponds,” Hammitt said. “Anybody near a water source could be in jeopardy depending on the severity of the storm.”
Two sinkholes have been reported on El Dorado County roads as a result of three days of rain this week. Residents have already filled 12,000 sandbags in preparation for the storm and an additional 20,000 were on the way in, Hammitt said.
“Anytime it’s Mother Nature, you have to be ready,” Hammitt said.
While Northern California faced the brunt of the storms, a less powerful system moved into Southern California overnight, bringing scattered showers Saturday morning. The rain was harder to the north along the Central Coast. The wet conditions should continue through the weekend.
But much of the concern is focused on the Bay Area and Sierra.
“It’s a once-in-10-year event,” said Zach Tolby, a meteorologist with the National Weather Service in Reno. “It’s the strongest storm we’ve seen in a long time, the kind of setup we look for to get significant flooding.”
Indeed, large swaths of the Bay Area, Sierra foothills, Central Coast and parts of the Sacramento Valley were under flash-flood warnings. Flood concerns are heightened because officials fear that the snow may quickly melt due to heavy rain.
The so-called atmospheric river of airborne moisture known as the “Pineapple Express” will be felt across much of the state this weekend, though rain will be much heavier in the north than in the south.
“It’s going to be like buckets of water for a fairly sustained period of time,” Tolby said.
Wind gusts on mountaintops could top 130 mph in the northern Sierra, which is typical, Tolby said. At lower elevations gusts could reach 30 or 40 mph, he said, “but that’s an average windy day for us.”
Tolby said the storm is packing the same wallop as an atmospheric river that hit Northern California a decade ago that caused $300 million in damage, according to the U.S. Geological Survey.
Angelenos may remember the 2005-06 storm because it was the first time it rained on the Rose Parade in 51 years. But Tolby, who lives in Lake Tahoe, remembers the storm differently.
“It was pretty wild. I was here in 2005 and it was definitely the hardest rain I’d ever seen. It didn’t stop for 24 hours,” he said.
This weekend’s storm could bring 36 straight hours of heavy rain from Mammoth Mountain to Susanville, Tolby said.
Below clear blue skies Friday, people in the snow-shrouded ski town of Mammoth Lakes were gleeful about the prospect of several more feet of snow.
Yet some also worried that the big, wet storm could dump so much rain and snow that it could shut down some ski runs or roads.
In preparation, snowplows were scraping icy roadways. Excavators and snowblower operators stayed busy clearing and moving huge piles of snow. Some cars sat abandoned on the roadside or at gas stations, covered with thick blankets of snow from the most recent storm.
Outside Kittredge Sports, store manager Terry Lucian took advantage of the clear weather to shovel away some of the mounds of snow that had built up outside the entrance.
“If the storm comes in as wet as they’re talking about, it’ll make for a big mess,” the 60-year-old said as he scooped icy snow off the entrance to the A-frame building.
Lucian said recent storms definitely helped to boost business, but he worried some skiers traveling to the area this weekend could be in for disappointment if storm conditions worsen to the point that they shut down parts of Mammoth Mountain.
“Everybody wants the snow, they just don’t want it while they’re here,” the 39-year Mammoth resident said. “It’ll be a rough couple of days, but we need the water. So it’s going to be OK.”
Up north, South Lake Tahoe Mayor Austin Sass urged residents to prepare for the storm.
“If at all possible, get up on your roof and get off whatever snow you have on there because the moisture combined with the snow will be extremely heavy and we’re worried about the integrity of your roof structure,” Sass tweeted Friday.
Do not go outside Sunday or Monday, he told his constituents.
“When the snow comes mixed with the rain, it’s going to be an absolute mess. So whatever you can do stay home, and most importantly, stay safe,” he said.
In the mountains, the rain could saturate the snow and trigger early melt, feeding extra runoff into watersheds already swollen from a week of rain.
“A combination of intense rain on saturated soils will lead to excessive runoff,” the National Weather Service said in its weekend forecast.
The Carson, Truckee and Susan rivers are all expected to become overwhelmed, and nearby communities may become increasingly isolated if the deluge triggers mud and rock slides.
Weather officials issued a flood watch from Saturday to Wednesday that covers much of Northern California and extends down through the Sierra to Tehachapi.
In Mono County, authorities offered sandbags to residents in preparation for the rain. In Yosemite National Park, officials announced Friday that the park would remain open through the wet weekend, but access to popular Yosemite Valley would be closed.
Earlier in the week, up to 2 feet of snow fell in less than 24 hours in the Tahoe basin on Wednesday, at times coming down at more than 2 inches an hour.
The Sierra Avalanche Center reported a slight improvement in backcountry conditions. The risk of avalanche was lowered to “considerable” even as the threat increased of historically large avalanches caused by slabs of snowpack as thick as 8 feet above a weak layer of ice laid down by a mid-December rain.
Near Lake Tahoe on Thursday, two skiers were caught in an avalanche that closed a local highway. But they were not injured, officials said.
Sierra residents are preparing for a third onslaught over the weekend, bringing up to 12 inches of rain below 8,500 feet, and more snow above that. A fourth storm system is forecast to roll across Northern California two days after that.
After the weekend storm, another rain-making system is expected to hit Northern California on Tuesday.
For all the problems the storms may cause, it will bring more good news for California’s six-year drought. Officials have said steady rain in Northern California the last few months has filled reservoirs and increased the once-anemic snowpack.
They emphasize the storms won’t end the drought. But if the rains keep up for spring, they could make a major dent.
St John reported from Colfax, Calif., Serna from Los Angeles, Barboza from Mammoth Lakes, Calif.
7:45 a.m. , Jan. 8: This post was updated with overnight news. 9:45 p.m.: This post was updated with death of woman.
4:45 p.m.: This story was updated with new details about road conditions from Caltrans.
3:45 p.m.: This article was updated with new details about residents of Mammoth Lakes preparing for a band of warm rain and possible flooding.
2:50 p.m.: This article was updated with new details about road conditions
11:15 a.m.: This article was updated with a revised weather forecast.
10:30 a.m.: This article was updated with a new forecast from the National Weather Service.
8:25 a.m.: This article was updated with information about road conditions.
7:30 a.m.: This article was updated with revised forecasts and rain reports in Southern California.
6 a.m., Jan. 7: This article was updated with storm developments.
9:30 p.m.: This article was updated with rain falling in Bay Area.
7:25 p.m.: This article was updated with information about flood risk.
3:40 p.m.: Jan. 6: This article was updated with details on storm preparations in the Sierra Nevada.
10:50 a.m. Jan. 6: This article was updated with comments from Sierra Nevada residents.
7:45 a.m. Jan. 6: This article was updated with new forecast details.
9:25 p.m.: This article was updated with information on the flood watch.
4:20 p.m. This post was updated with information on California’s drought.
3:11 p.m. This post was updated with information about L.A. rains.
2:10 p.m.: This post was updated with maps and updated forecast information.
This post was originally published at 12:20 p.m. Jan. 5.