Avalanche conditions were ‘considerable’ day of Squaw slide
December 30, 2008
OLYMPIC VALLEY ” The daily avalanche advisory posted by the Sierra Avalanche Center showed a “considerable” avalanche danger in backcountry areas on the day Randall C. Davis, 21, was buried and killed by an avalanche above Poulsen’s Gully at Squaw Valley U.S.A.
“Near and above tree lines on slopes steeper than 35 degrees, the avalanche danger is considerable on N-NE-E aspects with pockets of considerable on NW and SE aspects,” according to the Dec. 25 report. “Human triggered avalanches will be probable today. Use extra caution when traveling in the backcountry.”
Davis was found buried under several feet of snow in an area described as “heavily wooded, very steep and considered expert terrain,” by the Placer County Sheriff’s Office.
“No one witnessed the accident,” according to a Squaw Valley media release. “Ski Patrol noted apparent trauma due to impact with trees and avalanche debris in the area.”
Though the area Davis was found in match conditions considered dangerous by the Sierra Avalanche Center’s report, Andy Anderson, an avalanche forecaster with the Tahoe National Forest and Sierra Avalanche Center, said it is hard to say what the conditions were like near Poulsen’s Gully that day.
“Avalanche conditions inside resort boundaries will often vary due to a ski patrol’s different avalanche mitigation techniques,” Anderson said.
Recommended Stories For You
Explosives and ski cutting ” a defensive technique used by skiers and riders to trigger an avalanche on their own terms and then ride off for an island of safety ” are the most common avalanche control techniques ski patrols utilize, he added.
A reported 22 inches of new snow had fallen overnight and snow continued to fall heavily throughout the morning of the incident, according to the Squaw media release.
Earlier in the day ski patrol conducted avalanche control in the area using hand charges and ski cutting.
The last in-bounds avalanche fatality at Squaw occurred in 1963.
There have been two other in-bounds avalanche fatalities this season in the U.S., one in Wyoming’s Jackson Hole and one at Snowbird Ski Resort in Utah.
There are no typical avalanche conditions. But whether they are caused by wind, sun, or snow, avalanches will always occur when a snow pack rests on another weak layer of snow.
“The only other thing you need is a trigger,” said Anderson. “New snow is the most common avalanche trigger, though, the one we hear about the most is a person.”
Any time you have enough snow to recreate on, there is the potential for avalanche activity, Anderson added.
Terrain: The slope must be steeper than about 30 degrees and most often steeper than about 35 degrees. Slopes less than about 30 degrees are not steep enough to avalanche.
Snowpack: The snow must be unstable. Mountain snowpacks are a series of layers stacked on top of one another. Some of the layers are hard and strong, some of them are soft and weak. The snowpack is unstable when a harder stronger layer sets on top of a softer weaker layer and the soft weak layer can barely support the hard strong layer above it.
Trigger: A trigger provides the stress that causes the weak layer to collapse and the snowpack to avalanche. A trigger could be additional weight from more snow or it could be a person.
For more avalanche education and information about daily conditions visit http://www.sierraavalanchecenter.org
U.S. Fatalities: 9
Canada Fatalities: 0
Total Fatalities: 9
Dec. 27: Paintbrush Area; Jackson Hole, Wyo. Three skiers caught, and buried, none killed.
Dec. 27: Gravel Mountain; Grand Lake Area, Colo. Two snowmobilers caught, buried, and killed.
Dec. 26: North of Little Water Peak, Utah. One skier caught, buried, and rescued alive by companions.
Dec. 25: Red Dog Area; Squaw Valley, Calif. One skier caught, buried, and killed.
Dec. 24: Logan Peak; South Rodeo Grounds, Utah. Three snowmobilers involved, 2 caught, buried, and killed.
Dec. 17: Happy Chutes; north west of Crested Butte, Colo. One snowboarder caught, buried, and killed.
Dec. 14: Richmond Ridge, Colo. One skier caught, buried, and killed.
Dec. 14: Mt. Baldy, Snowbird Ski Resort, Utah. One skier caught, carried, buried, died later in the hospital.
Dec. 14: Red Pine Lake Area, Utah. One skier caught, carried, and injured