Avalanches one of several reported slides


Monday's fatal avalanche on Soda Mountain was just one of several potentially dangerous snow slides reported in the area this week.

Dale Atkins of the Colorado Avalanche Information Center said avalanche spotters reported six soft slab avalanches in the vicinity of Sand Mountain in North Routt County on Friday. And his office received an e-mail report, including a photograph, of a loose snow avalanche that knocked a skier down in the vicinity of Buffalo Pass during the weekend.

The recent avalanches show that, even when avalanche danger is not rated high, there is danger in the backcountry snowpack. Atkins said his office reported that there was considerable avalanche danger above 9,000 feet in the mountains north of Steamboat Springs on New Years Day. However, spotters reported seeing many snowmobile tracks in the Buffalo Pass area without any indication of snow slides. The Avalanche Information Center also received numerous reports of skiers tackling steep slopes on Buffalo Pass without incident.

"Snowmobiles are a good test -- they reported seeing lots of tracks and no slides at all," Atkins said.

The report of a skier being knocked down by a loose snow slide in the vicinity of Buffalo Pass and the upper north side of Fish Creek Canyon during the weekend was vague, Atkins said. The skier, who was shown in a fuzzy photograph, but was not named, was lying on his side in the snow. He was not buried in the slide thought to have happened Saturday. Atkin's information was that the small avalanche traveled perhaps 50 vertical feet.

Atkins said (the nonfatal release) was not a slab release -- the kind that poses the most danger for people in the backcountry.

"Loose snow avalanches are rarely a problem," he said.

Atkin's agency operates under the supervision of the Colorado Geological Survey and reports avalanche conditions in the northern, central and southern Colorado mountains. He said recent weather events in the backcountry surrounding Steamboat had varying effects on the stability of the snowpack at different elevations.

Atkins said the rain that fell in the valley and lowest mountain slopes Wednesday solidified the snowpack below 8,000 feet. The rain essentially froze the snowpack solid, making avalanche danger low at lower elevations, he said.

However, the strong southernly winds that buffeted the Park Range on Thursday and Friday after a light snowfall had the potential to load north-facing slopes with dangerous snow.

On Friday, the Avalanche Information Center rated the avalanche danger in the Steamboat zone moderate with pockets of considerable danger between 8,000 and 9,000 feet, with triggered avalanches probable above 9,000 feet.

Atkins said despite those general ratings, there is always avalanche danger in the backcountry and that the danger can vary across a single slope. Avalanche forecasters refer to this condition as "spatial variability."

Spatial variability also can explain why the last skier or snowboarder to travel down a slope can be the one to trigger an avalanche.

"You hit the one wrong spot, and everything crumbles," he said.

Atkins said his office would try to send a staff member to Soda Mountain to reconstruct what happened Monday.

"We try to look for lessons learned," Atkins said. "We try to look at terrain and snowpack and we try to interview survivors to learn what happened."

-- To reach Tom Ross call 871-4205

or e-mail tross@steamboatpilot.com


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