IL-9: Snow & Avalanche Forecasting
1.2 – Case Study
Case studies are accident accounts that can provide valuable insight into how people make decisions that lead to accidents. Read the following case study (or one supplied by the instructor) and consider how the components of the AIARE DMF apply to the decisions that were made. These are not “Darwin Award” candidates. They are regular backcountry recreationists who’s decisions led to unwanted consequences. Note that while this incident affected recreational backcountry users, professionals have made similar mistakes. This story underscores the fact that all humans are capable of making poor decisions. Following the case study there is an exercise to complete. While reading, make a note of any factors outlined in the DMF that in retrospect could have alerted the group about the risk to which they were exposing themselves. How could the team have created and chosen better options for the day? How could they have increased their margin of safety and still accomplished their goals?
ACCIDENT REPORT: OHIO PASS, COLORADO
Date: February 25, 2001 Location: East Bowl in the Anthracite Range, 7 miles west of Crested Butte, CO. The account below is condensed from a report written by Dale Atkins, who investigated the accident for the CAIC: The day dawned clear and cold after a 10” snowfall the day before. A group of 5 friends – two men and three women – met at the Kebler Pass trailhead and snowmobiled into the Anthracite Range, approximately 7 miles from Crested Butte, for a day of powder skiing in the backcountry. All of the group were experienced backcountry travellers familiar with the terrain, most having lived and skied in the area for 15 plus years. One member of the party was former ski patroller. Everyone had formal avalanche training and carried a transceiver, shovel and probe.
The public avalanche bulletin that day reported a danger level of “moderate with pockets of considerable at or near treeline.” The bulletin also noted that backcountry skiers in the Crested Butte area had reported triggering avalanches recently but had no information about where or when the avalanches had occurred. That day, the group left early and did not access the bulletin. The day was going well as the group skied laps on 30+ degree slopes in treed and open runs generally on northern facing aspects. The snow was perfect and they experienced no cracking and saw no avalanches. There were two other groups skiing in the same area.
On their last run they decided to ski “East Bowl” one of the available routes down to the snowmobiles. East Bowl, as the name implies, faces east and is a mix of treed and open slopes with a variety of terrain features such as convexities, wind rolls, small cliffs and many small trees. In general it is steeper than the terrain the group had been skiing that day with slope angles between 25-45 degrees. At the top, the group saw two ski tracks leading into the bowl. All was progressing fine when part way down the group split up into one group of 2 and one group of 3 with the plan to meet on a shelf in the trees above the last pitch. The group of 2 (Mitch and Sue) split up with Mitch skiing to the bottom beyond the meeting point and the other, Sue, meeting the group of 3, above the last pitch, insight of the snowmobiles at the bottom. The group had voice contact with Mitch at the bottom of the run a short distance away and Sue decided to traverse over to where he had skied down. On the traverse to the slope that Mitch had descended she intersected with a steep rollover, triggered and was caught in an avalanche. Sue remained on the surface but sustained a fatal head injury and died at the scene. Crested Butte lost a cherished member of the community that day.
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