- Location: Ophir Gulch, Aspen Mountain Side Country
- State: Colorado
- Date: 2010/02/26
- Summary Description: 2 skiers caught, 1 fully buried and injured
- Primary Activity: Sidecountry Rider
- Primary Travel Mode: Ski
- Location Setting: Sidecountry
- Caught: 2
- Partially Buried, Non-Critical: 0
- Partially Buried, Critical: 0
- Fully Buried: 1
- Injured: 1
- Killed: 0
- Type: SS
- Trigger: AS - Skier
- Trigger (subcode): u - An unintentional release
- Size - Relative to Path: R4
- Size - Destructive Force: D3
- Sliding Surface: O - Within Old Snow
- Slope Aspect: NW
- Site Elevation: 10534 ft
- Slope Angle: 43 °
- Slope Characteristic: Planar Slope,Sparse Trees
The avalanche occurred in steep, sparsely treed terrain below treeline in the side country, outside of the Aspen Mountain ski area boundaries. It was on a northwest facing slope. The average slope angle at the crown was 41 degrees with sections as steep as 43. It failed in a old weak layer of snow just above the ground.
On Thursday, the 18th of February, the Aspen area experienced a large winter storm. The first two days consisted of light snow with 5.5 inches of new snow accumulating at the mid-mountain weather station on Aspen Mountain Ski Area. This weather station sits at 10,150 ft and is the the closet observation site to the accident site. On Saturday the 20th through Monday the 22nd, the storm increased in intensity bringing another 28.5" of new snow. The storm slowly cleared on the afternoon of the 23rd. The storm total was 35 inches of new snow and 2.5 inches of water equivalent. Between the 23rd of February and the accident on the 26th, scattered snow showers deposited a few new inches of snow. The deep new storm snow layer formed the slab that released in the avalanche on the 26th.
During the winter season of 2009/2010, the Aspen area experienced below average snowfall, and several persistent weak layers formed in the snowpack. The northwest facing slope where the avalanche occurred had mostly facets and depth hoar making up the middle and lower snowpack. The large winter storm that occurred late in February, just prior to this injury, added a significant load of new snow to all these weak layers that made up the old snowpack.
Events Leading to the Avalanche
At approximately 3:30 pm on Friday February 26th, 4 skiers entered backcountry terrain outside the Aspen Mountain Ski area in the area of Ophir Gulch. Reports indicate that at the time of the avalanche, 2 skiers were standing above the crown of the avalanche in lower angled terrain, one was just below on a steeper slope digging a pit, and the fourth entered the path on the skiers right side of the slope and began skiing.
When the fourth member of the group entered the path, he triggered the avalanche and was carried approximately 500 vertical feet down slope, impacting a tree in the path, and ended up fully buried on the uphill side of the tree. His partner, who was also on the slope digging a pit at the time the avalanche initiated, was caught and carried a short distance but was able to grab a tree and avoid being swept down the path.
The buried skier was quickly found by a beacon search by one of his partners. He sustained serious chest and neck injuries in the impact with the tree that required a rescue and evacuation by 9 members of the Aspen Mountain Ski Patrol. The rescue group reached the Midnight Mine Road and a waiting ambulance at 8:40pm.
Figure 4: Snow profile from the crown of the avalanche.