Storm in Sierra Nevada sparks concerns about flooding, avalanches

Concerns about flooding, avalanches grow over storm in Sierra Nevada

The first band of what forecasters predict will be the region's most powerful storm in a decade moved into Northern California, prompting official warnings of widespread flooding and epic snowfall in the Sierra Nevada. Officials expected the storm to pack the same force as one that hit Northern California in 2005, causing $300 million in damage.

Officials reported scattered flooding and mudslides throughout the region on Sunday morning, notably in the North Bay, where several creeks and rivers were rising quickly. Motorists had to be rescued on the 101 Freeway in Sonoma County when the highway flooded. Several smaller roads were also closed due to flooding.

Local authorities were watching rising water levels at several key rivers, including the Truckee, Merced, Napa, American and Russian.

The flood danger is heightening, weather forecasters say, because of melting snow.

An “extreme” avalanche warning was issued for parts of the Sierra Nevada on Sunday due to heavy snow. In Mammoth Lakes, officials said higher elevation 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.

“Sunday night's our biggest concern,” said Jon Mittelstadt, a meteorologist with the National Weather Service based in Reno. “The biggest threat increases [Sunday], and then overnight into Monday — that’s when the rivers will be cresting.”

Mammoth Lakes residents girded for flooding as heavy rain fell Sunday morning, melting mounds of piled-up snow and sending water and slush into the streets of the eastern Sierra Nevada ski town.

"My garage is flooding with two inches of water," said Nick Criss, 40, as he shoveled sand into bags at the town public works yard.

Criss, a 12-year Mammoth Lakes resident, worries his home and many others will be damaged by the gush of rainwater and melted snow.

"There's nowhere for the water to go," he said.

Lifts at Mammoth Mountain resort were not operating Sunday morning because of high winds, thunder and lightning.

"Let's just say it's not a winter wonderland … high winds, thunder, lightning and rain in town," the resort wrote on its Twitter feed.

Visiting skiers and snowboarders were packing up their cars to head home Sunday morning.

As Mammoth Lakes emptied out, the town rattled with the crash of thunder, lightning and the sound of huge slabs of snow sliding off roofs onto the ground.

Erik Radatz, 45, who runs a pet grooming salon in Mammoth Lakes, rushed to shovel sand into sandbags to protect his home Sunday as the rain came down.

"If the temperature stays warm like this, it's going to be bad," Radatz said.

His advice for anyone from Los Angeles thinking of heading up to Mammoth?

"Stay home," he said. "But if you do come, don't bring skis — bring water skis."

The so-called atmospheric river of airborne moisture known as the Pineapple Express will be felt across much of the state, but especially in the Sierra, bringing with it warm snow-eating rain, forecasters said.

Mammoth Lakes residents worried that the warm rain and slush would dam up behind banks of shoveled snow piled high in empty lots and along roads throughout town, then flow wherever it could 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.”

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. The city of 8,000 is perched at an elevation of 7,880 feet.

On a winter war footing, 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 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.”

Crews and residents in area towns spent Saturday preparing for the deluge. Snowplow operators scraped icy roadways. Excavators and snowblowers cleared and moved huge piles of snow. In the eastern Sierra Nevada, Caltrans workers used explosive devices to clear snow from avalanche-prone areas.

“It’s the rain over the snow that we’re worried about,” said Greg Miller, Caltrans maintenance manager for the region. We’ve had snow since Christmas, but now, with the warmer trend, we’re worried about water.”

From his white SUV, Miller kept a close eye on conditions along U.S. 395. The reports heard over radio traffic told the story.

Cars rolling over and sliding off the road. An irate driver blocking a plow truck. Someone driving the wrong way on the highway.

At one point, a request went out to bump up to stricter tire chain controls as road conditions worsened. Later, a California Highway Patrol vehicle slid into a median and had to be pulled out.

“We’ve got cars everywhere, upside-down and everything,” Miller reported over the phone.

Maintenance crews were kept busy responding to snow-related accidents and icy road conditions.

Steve Coons manned 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 could feel the weight of the heavy, wet snow as it pushed against the plow blade and was 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 of it 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.

In Truckee, a small resort town north of Lake Tahoe, residents filled sandbags at the local fire station to shore their homes against the water.

Monique Long hefted heavy bags of sand into the back of her family GMC. The waist-high snow around her neighborhood was melting rapidly, and some of it was streaming down a nearby hill, straight into her garage.

“Everything is quickly coming up,” she said.

To the south in Mammoth Lakes, highway patrols responded to snow-related accidents as road conditions worsened.

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 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 up 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 that day.”

© Francine Orr/ Los Angeles Times/Getty Images Snow is visible through the clouds on the Eastern Sierra from Lone Pine, CA overnight November 21, 2016.

Storm in Sierra Nevada sparks concerns about flooding and avalanches

The first band of what forecasters predict will be the region's most powerful storm in a decade has moved into Northern California, prompting official warnings of widespread flooding and epic snowfall in the Sierra Nevada.

Officials expected the storm to pack the same force as one that hit Northern California in 2005, causing $300 million in damage.

Officials reported scattered flooding and mudslides throughout the region Sunday morning, notably in the North Bay, where several creeks and rivers were rising quickly. Motorists had to be rescued on the 101 Freeway in Sonoma County when the highway flooded. Several smaller roads were also closed because of flooding.

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Officials reported scattered flooding and mudslides throughout the region Sunday morning, notably in the North Bay, where several creeks and rivers were rising quickly. Motorists had to be rescued on the 101 Freeway in Sonoma County when the highway flooded. Several smaller roads were also closed because of flooding.

Live updates: Winter weather slams California
Live updates: Winter weather slams California
Local authorities were watching rising water levels at several key rivers, including the Truckee, Merced, Napa, American and Russian.

The flood danger is heightening, weather forecasters say, because of melting snow.

An “extreme” avalanche warning was issued for parts of the Sierra Nevada on 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.

“Sunday night's our biggest concern,” said Jon Mittelstadt, a meteorologist with the National Weather Service based in Reno. “The biggest threat increases [Sunday], and then overnight into Monday — that’s when the rivers will be cresting.”

The California Highway Patrol closed U.S. 395 in both directions in the eastern Sierra Nevada on Sunday morning due to storm-related flooding on the roadway near Mammoth Lakes.

U.S. 396 was closed to traffic about 11 a.m. from California 203 near Mammoth Lakes to the Crestview rest area because of flooding in the Smokey Bear Flat area, according to the CHP. Officials expect the closure to last at least two hours.

More than 91,000 PG&E customers in Central and Northern California were without electricity as of Sunday afternoon as rain, snow and winds caused flooding and knocked down power lines, said PG&E spokesman Paul Doherty.

Those who lost power were across PG&E's service area, which stretches from Bakersfield in the south to Eureka in the north.

In the San Francisco Bay Area alone, 33,200 customers didn't have power as of 2:45 p.m., Doherty said.

"Obviously we've seen the storm pick up in intensity today," he said Sunday afternoon.

Doherty said PG&E had prepared for the major storm and had extra crews — a total of 1,400 people — that were ready to respond to outages. The agency set up an emergency operations center in downtown San Francisco, as well as a staging area in the Santa Cruz Mountains to be prepared to respond to outages there.

Doherty said he expected most customers' power would be restored by late Monday, but that another strong storm was expected on Tuesday and Wednesday.

"We'll have our emergency operations center as long as necessary," he said.

Mammoth Lakes residents girded for flooding as heavy rain fell early Sunday, melting mounds of piled-up snow and sending water and slush into the streets of the eastern Sierra Nevada ski town.

"My garage is flooding with 2 inches of water," said Nick Criss, 40, as he shoveled sand into bags at the town public works yard.

Criss, a 12-year Mammoth Lakes resident, worries his home and many others will be damaged by the gush of rainwater and melted snow.

"There's nowhere for the water to go," he said.

Lifts at Mammoth Mountain resort were not operating Sunday morning because of high winds, thunder and lightning.

"Let's just say it's not a winter wonderland … high winds, thunder, lightning and rain in town," the resort wrote on its Twitter feed.

Visiting skiers and snowboarders were packing up their cars to head home Sunday morning.

As Mammoth Lakes emptied out, the town rattled with the crash of thunder, lightning and the sound of huge slabs of snow sliding off roofs onto the ground.

Erik Radatz, 45, who runs a pet grooming salon in Mammoth Lakes, rushed to shovel sand into sandbags to protect his home Sunday as the rain came down.

"If the temperature stays warm like this, it's going to be bad," Radatz said.

His advice for anyone from Los Angeles thinking of heading up to Mammoth?

"Stay home," he said. "But if you do come, don't bring skis — bring water skis."

Rain fell heavily overnight on Donner Summit, just west of Truckee, with nearly 4 inches by morning. Forecasters expect a total of 6 to 12 inches Sunday.

"It's turned the snow into cement, " said a tow truck driver for AAA. He had pulled six vehicles out of the slush pack by 10 a.m. Sunday and had other stranded drivers waiting, many of them in four-wheel-drive vehicles.

California Highway Patrol crews have repeatedly had to dig out ice dams blocking drainage culverts in Soda Springs, trapping stragglers from Saturday's ski rush in the mountains who are now trying to reach Interstate 80.

Slush and rain runoff is headed downhill into the Truckee River basin. The river, which rose from 1.5 feet on Saturday to 3.5 feet Sunday morning, is expected to top its banks at 4.5 feet Sunday afternoon.

The North Tahoe Fire District issued an avalanche warning for residents in the Incline Village area, warning them that expected collapse of snow will bring an "air wave" that will rattle windows. No structural damage is expected.

Matt Robinson, a spokesman for Sacramento County, says officials are inspecting the conditions of levees throughout the region. They are particularly concerned about the Cosumnes River, which is expected to begin overflowing about 5 p.m. Sunday, depending on the strength of the storm.

“These are areas that always flood when we have heavy rain,” Robinson said. “Some of these levees are old, and they may not be able to withstand the pressure.”

The worst flooding could be in Wilton, which is the southern part of Sacramento County. Officials announced a voluntary evacuation on Saturday afternoon, and a handful of people showed up at the evacuation center in Elk Grove Park.

The so-called atmospheric river of airborne moisture known as the Pineapple Express will be felt across much of the state, but especially in the Sierra, bringing with it warm snow-eating rain, forecasters said.

Mammoth Lakes residents worried that the warm rain and slush would dam up behind banks of shoveled snow piled high in empty lots and along roads throughout town, then flow wherever it could 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.”

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. The city of 8,000 is perched at an elevation of 7,880 feet. 

On a winter war footing, 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 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.”

Crews and residents in area towns spent Saturday preparing for the deluge. Snowplow operators scraped icy roadways. Excavators and snowblowers cleared and moved huge piles of snow. In the eastern Sierra Nevada, Caltrans workers used explosive devices to clear snow from avalanche-prone areas.

“It’s the rain over the snow that we’re worried about,” said Greg Miller, Caltrans maintenance manager for the region. We’ve had snow since Christmas, but now, with the warmer trend, we’re worried about water.”

From his white SUV, Miller kept a close eye on conditions along U.S. 395. The reports heard over radio traffic told the story.

Cars rolling over and sliding off the road. An irate driver blocking a plow truck. Someone driving the wrong way on the highway.

At one point, a request went out to bump up to stricter tire chain controls as road conditions worsened. Later, a California Highway Patrol vehicle slid into a median and had to be pulled out.

“We’ve got cars everywhere, upside-down and everything,” Miller reported over the phone.

Maintenance crews were kept busy responding to snow-related accidents and icy road conditions.

Steve Coons manned 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 could feel the weight of the heavy, wet snow as it pushed against the plow blade and was 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 of it 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.

In Truckee, a small resort town north of Lake Tahoe, residents filled sandbags at the local fire station to shore their homes against the water.

Monique Long hefted heavy bags of sand into the back of her family GMC. The waist-high snow around her neighborhood was melting rapidly, and some of it was streaming down a nearby hill, straight into her garage.

“Everything is quickly coming up,” she said.

To the south in Mammoth Lakes, highway patrols responded to snow-related accidents as road conditions worsened.

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 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 up 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 that day.”


California braces for flooding, avalanches as Sierra gets slammed with rain, snow

TRUCKEE, Calif. — A powerful storm blasted the Sierra Nevada with waves of torrential rain and heavy snowfall on Sunday, leaving a vast swath of California bracing for potentially disastrous floods, avalanches and mudslides.

The latest weather comes just days after the mountains around Lake Tahoe and Yosemite National Park received several feet of snow over the span of a week. At Mammoth Mountain, a ski resort bordering Yosemite, the 11,000-foot peak got 84 inches of snow in just two days. This week’s forecast calls for several more feet of snow, as well as heavy rain, part of a meteorological phenomenon known as the “Pineapple Express,” which brings an atmospheric river of warm moisture north from the tropics.

The conditions that accompany the latest band of moisture hovering over Northern California bear some semblance to those of a 1997 storm that flooded the Yosemite Valley and led to a years-long, $250 million recovery.

Park rangers closed roads onto the Yosemite preserve over the weekend, and local officials in mountain towns handed out sandbags for residents to reinforce their homes against the possible deluge.

The storm will continue to pound the Sierra Nevada range this week. Weather experts predict that colder temperatures could possibly turn the moisture from rain into heavy snow, bringing the potential for up to seven additional feet of snow in the mountains. At the highest elevations, the cold air could translate to as much as 20 feet of snow on the peaks, according to forecasts from the National Weather Service.

Such high snow accumulation could mitigate California’s enduring drought by building up the Sierra snowpack. Farming is a crucial aspect of the California economy, and the dry conditions and water shortages in recent years have hurt the state’s agriculture industry. The snowpack, which begins to melt in the spring, helps fill the reservoirs that are critical for growing crops during the summer months.

Frank Gehrke, the chief snow surveyor for the California Department of Water Resources, said the storm cycle — though potentially dangerous in the short term — could help quench the region’s drought conditions.

“This series of storms that we’re experiencing . . . are certainly going to have an impact on water supply, but we’ve got to wait and see how things settle out,” Gehrke said. “The ongoing concern is how warm or cold any particular event is. Warm can bring flooding, and a cold event can build the snowpack. That’s one thing we’re monitoring closely.”

As the storm settled over the mountains during the weekend, roads closed and resorts halted operations. Visitors had to be kept off the slopes, as extremely high winds and low visibility coupled with thunder and lightning made skiing too dangerous.

“We haven’t seen a storm cycle like this in the last five years of really heavy snowfall,” said Lauren Burke, a spokeswoman for Mammoth Mountain resort. “With the amount of rain that’s in the forecast, flooding is definitely on the forefront of people’s minds.”

In addition to flooding, the prospect of massive snows has experts concerned about catastrophic avalanches. The Sierra Avalanche Center issued a Category 5 warning and ranked the probability of hazardous conditions as “extreme,” noting that “due to significant loading from rain and heavy wet snow, natural and human triggered avalanches are certain in the next 24 hours.”

“We’re worried about infrastructure, roads, houses in avalanche zones, and potentially seeing some very large — up to historic — avalanches,” said Steve Reynaud, an avalanche forecaster at the center. “There’s high probability that things can slide big. Things that we haven’t seen potentially in a 10- to 20- to 30-year cycle.”

Brian Kniveton, a Truckee-area resident, joined volunteers at the Squaw Valley Fire Department to fill sandbags as the Truckee River swelled and carried chunks of floating ice.

“I just felt like paying it forward and trying to help do my part to keep North Lake Tahoe a community who can rely on each other,” Kniveton said.

This region of California has seen extensive flooding, but it has been quite a while since a system has come through with this kind of potential. Twenty years ago, Yosemite’s largest recorded flood was generated by a rainfall event not unlike what the park experienced this weekend. All of the park’s major floods resulted from a simple combination of warm rain falling on heavy snowpack.

In the 1997 storm, torrential rain melted the snowpack and the Merced River burst over its banks on New Year’s Day. Water levels in Yosemite Valley peaked at 16 feet, inundating park infrastructure. Electrical, water and sewer systems were shot, according to the park’s recovery report. The major roads into and out of the park were washed out, leaving more than 2,000 guests and employees stranded as they watched the floodwater pour into the valley.

“Every cliff was a waterfall,” a Yosemite spokesman told The Washington Post’s Ann Grimes in 1997. “Yosemite’s cliffs put Niagara Falls to shame.”

It took three days — during which time the water continued to rise — for the stranded parkgoers and residents to be evacuated by convoy. Downstream, 100,000 people were ordered to evacuate California’s Central Valley. On Jan. 3, 1997, the Merced River reached a record 23.43 feet at Yosemite’s Pohono Bridge, where flooding begins at 10 feet. The resulting damage was so significant that park officials closed Yosemite to the public until March 14, and even then, it was only partially reopened.

The federal government allocated more than $250 million to recovery and flood prevention projects, which weren’t fully completed until 2012.

This week’s cycle of storms began when high pressure — which has all but dominated California weather for the past five years — shifted east. Its absence allowed waves of low pressure to wash onto the West Coast.

Wind flows counterclockwise around low pressure, and swirling air draws warm moisture north from the tropics; the result is what’s known as an atmospheric river. Due to this particular phenomenon’s origins in the Pacific Ocean around Hawaii — and its ability to quickly beam storms toward the West Coast — meteorologists call it the “Pineapple Express.”

“We think of it as a fire hose, because that’s basically what it looks like,” said Jim Anderson, a meteorologist at the National Weather Service in Hanford, Calif.

That fire hose of moisture poured down over much of California as rain and snow in two sessions — one at midweek and a second, stronger wave during the weekend.

Between New Year’s Day and Thursday, Squaw Valley ski resort north of Lake Tahoe racked up 83 inches of snow on its peaks. Areas west of the peaks were slogged with nearly 10 inches of rain in 48 hours.

Highways through the Sierra Nevada, including Interstate 80 at Donner Pass, were closed during the heaviest snow. When they reopened, six-foot walls of snow towered on the shoulders, and traffic crept through the wintry tunnels.

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