Massive storm system moves into Northern California; flooding, heavy snow forecast - Los Angeles Times
The first band of what forecasters predict will be the region’s most powerful storm in a decade moved into Northern California on Saturday, prompting official warnings of widespread flooding and epic snowfall.
“People are definitely in a state of panic right now,” said El Dorado County Sheriff’s Sgt. Todd Hammitt. “We’re getting a lot of calls asking if we’re going to be able to deal with everything. It’s the general pandemonium of not knowing what’s coming.”
The epic system — known as an atmospheric river — could dump so much rain and snow that some ski runs and roads will be declared off-limits, with forecasters warning of significant flooding, mudslides and avalanches in the Sierra Nevada.
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.
This weekend’s system could bring 36 consecutive hours of heavy rain from Mammoth Mountain to Susanville, in Lassen County. Though that is good news for California, which is entering its sixth year of drought, the coming rain could melt already standing snow — feeding watersheds swollen from storms earlier this week, forecasters said.
“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.
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 morning released a new timeline for the storms:
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. County residents have already filled 12,000 sandbags in preparation for the storm and an additional 20,000 are 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 on and off through the weekend.
But the much of the concern is focused in 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.
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UPDATES:
11:15 a.m.: This article was updated with more details about the 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.
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