Avalanche Details
- Location: No Name Peak, Berthoud Pass
- State: Colorado
- Date: 2010/01/11
- Time:
11:25 AM
(Estimated)
- Summary Description: Cornice broke under person, caught, carried, not buried
- Primary Activity: Backcountry Tourer
- Primary Travel Mode: Foot
- Location Setting: Backcountry
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Number
- Caught: 1
- Partially Buried, Non-Critical: 0
- Partially Buried, Critical: 0
- Fully Buried: 0
- Injured: 0
- Killed: 0
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Avalanche
- Type: HS
- Trigger: AC - Cornice fall triggered by explosive action
- Trigger (subcode): u - An unintentional release
- Size - Relative to Path: R2
- Size - Destructive Force: D2
- Sliding Surface: O - Within Old Snow
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Site
- Slope Aspect: E
- Site Elevation: 12240 ft
- Slope Angle: 35 °
- Slope Characteristic: Cornice,Below Cornice
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Weather Summary
The day was sunny, warm, and almost calm. There was approximately "10 to 15 inches of unskied snow" from a storm four days prior.
Snowpack Summary
The CAIC danger for the Front Range on 01/11 was "CONSIDERABLE on all slopes above treeline" and the forecast mentioned 3 large avalanches above treeline in the Berthoud Pass area in the prior three days. There was a recent, possibly skier-triggered, avalanche about 150 feet to the north that the party noted.
Events Leading to the Avalanche
Skier 1 descended "Oatmeal Bowl," a lower angle south aspect on other side of the bowl. The rest of the party watched from the summit of No Name.
Skier 2 reported "I was considering launching the 10' cornice... [and was] worried about is the whole slope ripping out on me when I land." Skier 2 grabbed several rocks to throw onto the slope "to see if anything would release.†He was about 5 feet from the edge of the cornice when it broke. Skier 3 was watching and said "it was like falling through a trap door, it happened so fast."
Skier 2 fell about 20 feet onto the slope below. He landed on his back and immediately rolled over and attempted to self arrest. He "feel the snow below me releasing" before additional cornice fall peeled him off.
Accident Summary
"I was swimming towards the top the entire time. I went over a 10-15' rock band in the middle, I think this buried me below the snow as I fell. [Skier 3] who watched the entire incident said I was below the snow in this bottom section for approximately 75-100', he also estimated my speed at 40-50mph. At one point I swam to the top … and yelled out "HELP!" I continued swimming to the top and now had some snow forced down my throat. I began punching for an air pocket and continued swimming as I felt the snow begin to slow down. I ended up on top of the snow in the middle of the runout. My helmet was on top of the snow about 20' below me. The entire fall from top to bottom was approximately 15-20 seconds."
Rescue Summary
Skier 3 watched the entire avalanche. The other party members on No Name got out beacons and began to plan a safe route down. Skier 1 also prepared to search.
Skier 2 stood up, "took 4-5 steps and fell down, feeling punch drunk. I took another 4-5 steps and fell down again. I had snow everywhere - jacket, pants, ears, nose, mouth, hair. I was unscathed, save for a bit of soreness in my back, shoulders, and legs."
An easily carried rock is not an effective stability test. As Tremper writes in Staying Alive in Avalanche Terrain a cornice chunk "the size of a refrigerator or small car" is effective. "The smaller the cornice, the less effective the test." The goal is to stress the slope much more than a rider will.
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