CAIC: Colorado Avalanche Information Center

2012/01/18 - Colorado - Burnt Mountain Near Snowmass Village

Published 2012/02/18 by Brian McCall/Scott Toepfer/Brian Lazar - Forecaster, CAIC


Avalanche Details

  • Location: Burnt Mountain Near Snowmass Village
  • State: Colorado
  • Date: 2012/01/18
  • Time: 1:30 PM (Estimated)
  • Summary Description: One skier caught, buried and killed.
  • Primary Activity: Sidecountry Rider
  • Primary Travel Mode: Ski
  • Location Setting: Accessed BC from Ski Area

Number

  • Caught: 1
  • Partially Buried, Non-Critical: 0
  • Partially Buried, Critical: 0
  • Fully Buried: 1
  • Injured: 0
  • Killed: 1

Avalanche

  • Type: SS
  • Trigger: AS - Skier
  • Trigger (subcode): u - An unintentional release
  • Size - Relative to Path: R2
  • Size - Destructive Force: D1.5
  • Sliding Surface: G - At Ground/Ice/Firm

Site

  • Slope Aspect: NE
  • Site Elevation: 10490 ft
  • Slope Angle: 50 °
  • Slope Characteristic: Planar Slope

Avalanche Comments

This was a small avalanche triggered from the bottom of the path in a terrain trap. Witnesses noted that Skier 3 dropped into the gully on a steep slope and got stuck in the debris of a small avalanche triggered just moments before by Skier 2. As Skier 3 struggled to extricate himself from the snow at the bottom of the gully, he triggered and was buried by a second avalanche that came down the slope he had just skied.

Weather Summary

On Monday January 16th a snow storm brought 9 inches of new snow to the neighboring Snowmass ski area. The new snow was accompanied by moderate to strong southwest winds. The day of the accident the skies were mostly cloudy with moderate to strong southwest winds and mild temperatures.

Snowpack Summary

The snowpack in 'Wilkinson' Gully was composed of a soft storm slab in the upper snowpack from the new snow that fell two days prior to the accident. Below this was a surface hoar layer that formed around January 1st. The early-season snow in the lower snowpack had turned to large depth hoar, with grains up to 6 mm in size. At the time of the accident the surface hoar layer was buried under the storm slab about 20 cm below the snow surface. The avalanche may have failed initially on this surface hoar layer. Test results indicate it would have quickly stepped to the ground after being triggered.

Events Leading to the Avalanche

Skier 1 entered the slope and descended in the bottom of a prominent gully that runs along to the north on Burnt Mountain. Skier 1 started at the top of the gully and skied down about 400 feet. Skier 2 entered the gully about 50 feet lower than Skier 1 on a short, northeast facing slope. Skier 2 triggered a small soft-slab avalanche from low on the slope. Skier 2 was not caught in this avalanche. He continued to ski down the gully for approximately 200 feet.

Accident Summary

Skier 3 entered the same gully another 25 lower than Skier 2 on a short, but very steep northeast facing slope. Skier 3 skied straight down the fall line of this slope without turning and into the gully bottom. He became stuck low on the slope in the debris from the small avalanche triggered by skier 2 and the weak faceted snow below that debris pile. While struggling to get out of the snow and move downhill, he triggered a small soft-slab avalanche on the sidewall of the gully. This avalanche ran down into the gully, knocking skier 3 over and burying him in debris at the bottom of this terrain trap.

Rescue Summary

Skier 2 watched the avalanche bury his partner. Skier 1 was further down the gully and out of view. Upon witnessing the avalanche, Skier 2 shouted for Skier 1, and they both walked back up the gully through deep snow to the avalanche site. As they reached the debris, two other parties including three snowboarders and two skiers, descended down on the accident site. There were a total of seven people searching for the buried skier. The victim was not wearing an avalanche beacon and none of the seven searchers carried shovels or probes. With limited resources for a rescue, they began digging in a likely burial location near the last seen point with their hands and snowboards used as a shovels.One of the rescuers noted that initially, they dug in the wrong location. This victims foot was found first slightly uphill from where they thought he would be buried. Group members estimate that it took about 10 minutes to find his exact location. A member of the second group on scene called 911 dispatch with a cellular phone. The call was routed to the Snowmass Ski Patrol who helped talk the group through rescue procedures. They also responded to the scene, which was just outside the ski area boundary, with rescue and evacuation equipment.

Comments

This was a very small avalanche that had very large consequences. The avalanche ran into a steep sided gully, which created a deep pile of debris that was confined to a small area. This type of terrain is often called a terrain trap, because an avalanche in a gully produces a deeper burial than on an open slope.
The group carried standard alpine skiing equipment. The other two parties that helped with the rescue also were on alpine equipment and snowboards. They did not have avalanche rescue equipment or equipment to travel uphill. It is impossible to say if carrying these items would have produced a different outcome, but they could have reduced the time to travel up the gully, and locate and extricate the victim.

Media

Video

Images

Snowpits

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Figure 11: A snow profile conducted 6 feet below the crown face along the skier's left flank of the avalanche.