CAIC: Colorado Avalanche Information Center

2012/01/22 - Colorado - Prima Cornice, Vail

Published 2012/03/06 by Scott Toepfer - Forecaster, CAIC


Avalanche Details

  • Location: Prima Cornice, Vail
  • State: Colorado
  • Date: 2012/01/22
  • Time: 1:10 PM (Estimated)
  • Summary Description: 3 skiers caught, 1 injured, and 1 partially buried-critical and killed.
  • Primary Activity: Inbounds Rider
  • Primary Travel Mode: Ski
  • Location Setting: --

Number

  • Caught: 3
  • Partially Buried, Non-Critical: 1
  • Partially Buried, Critical: 1
  • Fully Buried: 0
  • Injured: 1
  • Killed: 1

Avalanche

  • Type: SS
  • Trigger: AS - Skier
  • Trigger (subcode): u - An unintentional release
  • Size - Relative to Path: R3
  • Size - Destructive Force: D2
  • Sliding Surface: O - Within Old Snow

Site

  • Slope Aspect: NE
  • Site Elevation: 10800 ft
  • Slope Angle: 46 °
  • Slope Characteristic: Planar Slope

Avalanche Comments

The avalanche was a soft slab, triggered by a skier, medium sized relative to the path, large enough to bury and kill a person. The slab broke on the ground and in an old snow layer near the ground (SS-AS-R3D2-O). The crown averaged about 18 inches deep, and the avalanche was about 200 feet wide and ran an estimated 400 vertical feet. The avalanche started on a northeast aspect at 10,800 feet. The average incline of the start zone was 46 degrees.

Weather Summary

A powerful winter storm dropped 9 inches of snow January 21, 2012 with strong southwest winds that backed to the northwest as the storm was ending. Snowfall decreased but continued at a lesser rate into January 22.

Snowpack Summary

The Colorado snowpack during the fall of 2011 and early winter of 2012 formed from a few small snowstorms during an extended period of dry, cold weather. The snowpack was generally thin, with the deepest snow cover on north to east aspects. The snow on the ground between mid-October and mid-January formed into a very weak layer of depth hoar crystals.

We performed a snow profile on January 23rd about 100 vertical feet below the crown face of the avalanche. The snow layers included a hard layer of old depth hoar near the ground. This layer was about 9 cm thick. Above this hard layer was about 50 cm of well-developed and very weak, faceted snow grains and depth hoar. Above the depth hoar, there was a 35 cm thick soft slab, formed during two snowstorms (Martin Luther King weekend and the storm on January 21-22). The slab included several layers of small facets, near-surface facets, and decomposing precipitation particles.

Events Leading to the Avalanche

Five skiers entered the Prima Cornice area through the Lower Prima Cornice gate. Skiers 1, 2 and 3 began hiking or sidestepping uphill to the south along the rim of the Prima Cornice. Skiers 4 and 5 quickly decided to stop hiking and skied down about 200-300 vertical feet to a bench in the slope. Skiers 4 and 5 waited for the other three at this bench.
Skiers 1, 2, and 3 continued hiking/sidestepping until they were approximately 120 linear feet uphill and to the south of the Lower Prima Cornice gate. From the rim of the Prima Cornice, they traversed south and further out into the Prima Cornice area. The three skiers were in the Prima Cornice area at the time the avalanche released. From examining physical evidence and eyewitness testimony, we were unable to determine the exact locations of the skiers when the avalanche released.

Accident Summary

Skiers 1, 2, and 3 were all caught in the avalanche. Skier 1 was the furthest south on the slope. The avalanche carried Skier 1 through the spruce forest until he came to rest against a tree, partially buried-critical with both skis and one arm above the snow surface. The burial location was approximately 50-75 feet below a traverse track present on the day we visited the site (January 23, 2012). The avalanche carried Skier 2 until he struck and grabbed a tree. He lost both ski poles and gloves in the ride and one ski was knocked off. The tree where Skier 2 came to rest was very near the traverse track present on the day we visited the accident site. The avalanche knocked Skier 3 off a small cliff. He tumbled and when he came to a rest, he was out of the debris and not buried.

Rescue Summary

Vail Ski Patrol was notified of the avalanche and responded to the scene where they found the avalanche and Skier 1. Skier 1 was transported off of the mountain and to a medical facility. The coroner reported that Skier 1 died from injuries sustained in the avalanche.

Comments

This accident occurred within the Vail ski area boundary. The ski area stated the Upper Prima Cornice area was closed. This is relevant to this investigation because a professional avalanche safety group (Vail Ski Patrol) had begun mitigating the avalanche hazard in the Prima Cornice area, but their work had not progressed to the point where they would allow the public into the area accessed from the Upper Prima Cornice gate.

The skiers involved in this accident told the Eagle County Sheriff’s investigator that they skied past the closed Upper Prima Cornice gate and then entered the area through the Lower Prima Cornice gate, which was open. Three of the skiers then followed tracks as they hiked/sidestepped and then traversed towards the area where the avalanche occurred.

CAIC staff visited the accident site on January 23, 2012. That day there were numerous ski and snowboard tracks in the area and along the rim of the Prima Cornice area. Since we do not know exactly when the tracks were made, we cannot completely rule out the possibility that another rider, not in this group, triggered the avalanche.

Vail Daily article

Media

Images

Snowpits

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Figure 12: Snow profile done just a few feet north of Skier 2's location. This profile was observed on January 23rd.