Analyzing avalanches

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Analyzing avalanches
Backcountry forecasters study snow stability

By David Bunker
Sierra Sun, http://www.sierrasun.com
January 5, 2007

Every winter, snow slides and people die.

That reality is at the front of Brandon Schwartz’ mind as he pokes his unwieldy probe into the snow atop Tamarack Peak, near Mount Rose.

Meanwhile, fellow avalanche forecaster Andy Anderson is stooped over a shallow snow pit, peering through a magnifying glass at snow crystals that hint at the slope’s stability.

The snow, glimmering like shards of broken glass under his lens, is changing even as Anderson studies it. The sun, wind, humidity — a handful of variables — all conspire to make the slope either a deadly trap or a solid, skiable descent.

The fact that Schwartz and Anderson are out testing for avalanche danger is something of a miracle. Last year at this time, the Truckee-based Sierra Avalanche Center was running out of funds, Schwartz was on back pay and the center was on the verge of folding.

“It was very grim last year,” said Bob Moore, the U.S. Forest Service supervisor who heads up the avalanche center at the Forest Service ranger station in Truckee.

At a time when backcountry skiing is booming, the Forest Service’s avalanche center relies heavily on private donations. The sport’s popularity places hundreds of skiers and snowboarders in potentially deadly avalanche terrain all around Tahoe each season.

Those skiers and businesses came through last year with private donations and fundraising days.

Mount Rose, Sugar Bowl, Homewood and Kirkwood will each put on a Sierra Avalanche Center ski day this year, where discounted lift tickets are sold to fund the center.

That funding, along with $17,500 from the Forest Service, helped the center hire a second forecaster, a move that means more avalanche terrain can be analyzed, leading to more informative forecasts.

“We’ve got two sets of eyes looking at everything,” Schwartz said. “We have someone to bounce things off of.”

A bulletin for the backcountry
The value of the avalanche center’s work is illustrated by the Web traffic their avalanche advisory generates every time it snows.

The number of page views on a storm day regularly ranks well over 1,000.

The advisory gives a thorough description of terrain that may be avalanche-susceptible — taking into account the strength and direction of the wind and sun exposure.

“The [Forest Service’s] investment in increased avalanche study and forecast is a commendable response to an obvious growth in both motorized and nonmotorized winter backcountry use,” said Mark Kircher in an e-mail interview.

Kircher, a regular backcountry skier over the last two decades, said he believes the Internet bulletin is a great way to communicate with the burgeoning population of young backcountry skiers and snowmobilers.

Brent Cutler, owner of the Sports Exchange in Truckee, donated raffle prizes for a fundraiser for the center last year. He says the avalanche forecasts are critical in the growing sport of backcountry skiing, where many new and inexperienced users are taking up the sport.

“I think now it’s more needed than ever,” Cutler said. “It’s pretty much the only tool that backcountry skiers can reference.”

The avalanche forecasters emphasize that the bulletins are not meant to be substituted for thinking on your feet in the backcountry. The advisory is only a warning.

“At the same time, all it is is an advisory,” said Schwartz. “It’s just a place for someone to start their day from.”

Anderson agreed, saying the forecast is as much a backcountry tool as a shovel, probe and avalanche beacon.

The advisory, meanwhile, has been perfected over the last two years since the center teamed up with the National Weather Service office in Reno. The experts there provide Schwartz and Anderson a specific backcountry weather forecast to use in modeling how storms will affect snow stability.

“Before, we weren’t giving them enough information,” said Rhett Milne, a forecaster in the Reno NWS office. “We realize that there are a lot of people that go out into the backcountry.”

Tahoe’s avalanche danger
Tahoe has very different avalanche conditions than Colorado or Utah, where high avalanche danger can extend for a month or more at a time. But that does not mean that Tahoe’s slopes are any safer on any given day than any other part of the nation.

“There is a very real danger that exists here,” Schwartz said. “Avalanches happen here. I see hundreds every winter.”

Deaths from avalanches usually register between 20 and 30 per year in the United States, according to the avalanche Web site avalanche.org.

Already this winter, one skier and two snowmobilers have died entombed in snow slides in Colorado, Montana and Wyoming.

Last winter, a backcountry skier died in an avalanche along the eastern Sierra Nevada near Bridgeport. In previous winters, avalanches have claimed lives near Mount Anderson, below Castle Peak and at Mount Judah.

Danger and Beauty
Tahoe is a gleaming sea of blue below Tamarack Peak, as Schwartz sidesteps down a chute, testing the depth of the snow.

Anderson watches and records the information Schwartz spits out, using words like “depth hoar,” “facets” and “surface crust.”

Anderson jokingly labels himself a “snow nerd,” but the snow science is deadly serious.

As Schwartz puts his ski into a wind drift, Anderson calls out.

“Check out, just below your skis you can see those two, even three cracks that formed right in that drift,” said Anderson.

It’s a small warning that a less experienced person might have missed.

And it’s one more hint the two will pass along to Tahoe skiers to help them stay alive in the backcountry.

“You get to spend a lot of time outside, but you have to think while you are doing it and know a little science — actually a lot of science,” Anderson said.

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For the tahoe area: http://www.sierraavalanchecenter.org/
For the Eastern Sierra/Mammoth area: http://www.esavalanche.org/
and for other centers and info: http://www.avalanche.org/