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Avalanche Danger Lurks in Southern California Mountains

May 7, 2017
By Suzanne Hurt, The Press-Enterprise, Riverside, Calif.

Jan. 28--Experts are warning about continued avalanche risk above 8,000 feet in Southern California mountains after two hikers using crampons and ice axes survived a 3,000-foot avalanche and were rescued by helicopter from Mt. Baldy last week.

San Bernardino County Sheriff's deputies and firefighters hoisted out the pair, who slid about 1,000 feet after they and a third hiker possibly triggered the avalanche during an ascent of Baldy Bowl on the south face of the peak at about noon Thursday, Jan. 26.

"As soon as it broke free, one of the hikers yelled 'Avalanche!' and they were all tumbling," said San Bernardino County firefighter/paramedic Eric Sherwin, a department spokesman.

Backcountry skiers and/or mountaineers using the Sierra Club's nearby San Antonio Ski Hut, an overnight shelter, wrapped the two injured men -- Long Beach resident Cody Ayala, 27, and Chris Chung, 32, of Irvine -- in blankets and tied one into an ice-axe anchor to keep him from sliding further before emergency personnel arrived.

While the third hiker was uninjured and able to hike out, Ayala and Chung were at times buried beneath the snow but came to the surface as they stopped a third of the way down the slide, which continued another 2,000 feet -- highlighting the potential danger of avalanches.

Signficant risk to Southern Californians remains for those who venture high into the region's snow-covered San Gabriel, San Bernardino and San Jacinto mountains following last week's heavy snowfall.

Recent strong winds and warm temperatures are just adding instability, especially on southern slopes, said So Cal Snow Avalanche Center founder/President Allen Giernet.

"It's a crazy situation we're dealing with, 'cuz we don't get avalanches here very often," said Giernet, who teaches avalanche safety classes.

"But when they do happen, it can be very serious because we have such a large population surrounding these mountains," he added. "They don't generally look at these mountains as serious mountains, but they are."

The last Southern California avalanche deaths were in 2008. Three backcountry skiers died in avalanches on the same day outside the boundaries of Mountain High near Wrightwood.

Since 1950, at least 64 people have died in avalanches in California -- with nine of those in Southern California, Giernet said.

Avalanche basics

An avalanche is a mass of snow, and sometimes ice and rocks, sliding downhill.

Avalanches require four things: a steep-enough slope, usually 30 to 45 degrees; a weak or sliding layer beneath surface snow; a slab or block of snow above a weak layer; and a trigger, U.S. Geological Survey avalanche expert Erich Peitzsch said.

The trigger could be human -- a hiker, skier, snowmobiler or snowshoer -- or more snow. But noise -- like someone yelling or laughing because they're loving that fresh powder -- doesn't trigger an avalanche.


"Noise? No. That's a myth," said Peitzsch, a scientist with the U.S.G.S. Northern Rocky Mountain Science Center.

High winds kept Giernet and a team from going up 10,064-foot Mount San Antonio or "Mount Baldy" to investigate the avalanche Friday at Baldy Bowl, which sits just below the San Gabriel Mountains' highest peak.

Giernet believes the avalanche was triggered when at least one of the three hikers, who traveled to the bowl via the San Antonio Ski Hut/Baldy Bowl Route, stepped into a soft slab of wind-loaded snow that wasn't well-bonded to layers beneath it. The slab broke loose.

Wind during the last storm likely transported snow from the northern side of the ridge top into the bowl and left rounded, smooth pillows of snow. Layers of ice, rain and/or hard-packed snow may have kept the softer wind slab from connecting well to the base layers of snow, Giernet said.

Giernet warns against traveling in avalanche terrain and on slopes greater than 35 degrees above 8,000 feet in any of the region's mountains. Natural avalanches are possible and human-triggered slides are likely, he said.

Peitzsch said it doesn't have to be snowing to put more weight on a weak layer of snow. Wind moving snow is enough.

"We sort of say wind is the architect of avalanches," he said. "You can have wind moving snow from one side of the mountain to another. When it does that, it creates a bigger and bigger slab."

Avoiding danger

The best way to avoid an avalanche is to take an avalanche safety class.

Travel with a partner, carry survival equipment and first aid, and in avalanche terrain, wear an avalanche beacon and carry collapsible avalanche probes and avalanche shovels.

Watch for red flags: recent abundant snow; strong winds moving snow; rain on snow, which quickly adds weight; a warm, sunny day, which can decrease the snowpack's strength, Peitzsch said.

"If you haven't taken an avalanche class, it's basically best to just stay out of avalanche terrain," he said.

Contact the writer: 951-368-9444 orshurt@scng.comTwitter: @SuzanneHurt

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(c)2017 The Press-Enterprise (Riverside, Calif.)
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Story Image: The sun is seen setting behind the mountains in Phelan, Calif., January 25, 2017. (Courtesy of Bob-O, WeatherBug user)