How To Learn from Avalanche Accident Reports

How To Learn from Avalanche Accident Reports

This past backcountry ski season, 2020-2021, was a tragic winter in both Europe and North America, with fatalities above the annual average. While avalanche agencies dug into the data to observe trends and identify factors that led to an increase in accidents (read Powder Cloud’s take on the 2020-21 season in the U.S. here), many of us guides and avalanche professionals reviewed our local accidents in the hope that we could mitigate the trend in our own backcountry zones. (The Colorado Avalanche Information Center or CAIC provides state and national incident data on their site, as does Avalanche Canada.)

As a professional, I continue to learn from near misses and accidents. An avalanche occurrence provides direct evidence of unstable snow, and therefore provides invaluable information about the hazard. Because local investigations are careful to avoid speculating about unproven factors that may have led to decision-making errors, the published incident reports stick to the facts summarizing avalanche characteristics, weather and snowpack factors, and a timeline of events including the rescue and evacuation response.

Our responsibility is to learn from each avalanche accident report to help us avoid making the same mistakes. In order to glean important lessons from these factual reports, we find it helpful to analyze them in a way that puts us in the shoes of those involved. Recreationalists can do the same. Here is an outline of the questions we ask ourselves after reading each report—hopefully this can help inform part of your strategy this winter.

Question No. 1: What was the problem and where did it occur?

Identify the avalanche release type, the depth of the bed surface or weak layer, how much of the slope released, and the size and destructive nature of the avalanche. Compare that to the region’s forecast avalanche problems.

Note the elevation of the start zone—and the aspect of the slope to wind and sun. Was it a sunlit slope that released in the afternoon? Was it a wind-loaded slope near ridge top? Or was it a steep, sheltered opening in the forest? If photos are provided, look closely at the terrain characteristics and refer to the reported slope angle. Analyze the shape of the start zone and the trigger point.

Whether or not you are familiar with the terrain where the avalanche occurred, this information gives you a clear picture of the slopes you will plan to avoid tomorrow.

Photo by Colin Zacharias. One of the best ways to learn about terrain is to see it just after the avalanche event, and to keep that image in mind every time you visit that drainage.

Question No. 2: Why was this event unexpected?

Most backcountry riders have no intention of triggering an avalanche. Therefore, regardless of the involved group’s terrain or snowpack familiarity, there is usually some factor or uncertainty that contributed to make the accident an unexpected event.

Maybe the danger was high, but the slope was low-angled and rarely naturally avalanched. The skiers likely thought the slope was safe, but unfortunately it released. This happens somewhere almost every year (“I’ve never seen that slope slide!”). The culprit is usually a persistent weak layer, and often the slope is connected to adjacent steeper terrain (see Powder Cloud’s Terrain Tip 3: Steep Enough to Slide).

Or perhaps in another case the danger was rated low and the party didn’t expect to trigger an avalanche, but they were backcountry skiing in a Rocky Mountain snowpack where “low danger never means no danger.” As a colorful forecaster once told me, “When that damned depth-hoar base layer blankets the range, I don’t trust steep slopes until the glacier lilies poke through in July.” 

Sometimes folks simply didn’t recognize that they are in avalanche terrain. Perhaps they were traveling across a low-elevation meadow that they thought was caused by a boulder field and not a snow avalanche. Or they were sledding through a logging block and hadn’t thought of the cleared slope as an avalanche path. If the snow is unstable and the slope is steep, it only takes a slope as long as an NHL hockey rink to avalanche (no apologies for my Canadian analogy). Recognizing how people see terrain differently helps us inform and support the decisions of our backcountry travel partners.

The avalanche accident reports will at times include a summary comment on the avalanche’s unexpected nature. This may include the perspective of either the investigating team or persons involved. Pay close attention. When those involved identify an unexpected event as a lesson learned, it can become our lesson applied.


Question No. 3: What can I learn from the rescue and recovery response?

There is no more sobering element of the avalanche accident report than the description of the avalanche recovery and first aid and evacuation response. We can always learn from what worked and what did not.

Often a self-rescue response is affected by communication and organizational challenges, a lack of time or equipment, the onset of hypothermia, and/or impending darkness. A self-rescue response, especially of a completely buried and injured victim, is often a bleak prospect. You don’t want to get caught in an avalanche in the remote backcountry. A quick read through the affected team’s self-rescue efforts usually brings up a few questions:

  • Was the last person in the party able to call on their cell phone for help? Did they use a satellite texting device?
  • Did the group’s own response make a difference—or was an agency rescue team called in to respond?
  • Companion self-rescue almost always takes too long. What do I need to do to be more efficient and effective? How do I get better at organizing a team response, searching with a transceiver, probing, and team shoveling?
  • Does my kit include an evacuation sled? What if there is no available heli-evacuation, the weather is too bad for a heli to land, or it will take hours to arrive? How will we get our injured team member to a higher level of care before they succumb to their injuries or hypothermia?


The Bottom Line

The bottom line is we always learn from these accident reports. We try to put ourselves into the place of those involved and identify errors. We hope this analytical exercise can prevent this incident from happening to us at some future date.

When we do this, it’s going to involve some speculation on our part. Keep in mind that if you weren’t there, you don’t have all the facts, and therefore you should not pass judgement (the point of this is to learn, not to derogate). And importantly, you have to put yourself in the position of making terrain choices prior to the avalanche occurring. The avalanche occurrence is key info you would not have had prior to leaving the trailhead.

As most accident reports don’t include information about human factors that challenge the decision-making, it’s helpful to sit down with our mates and discuss and visualize what we might have done in the same situation. In an abstract way, this can form a memory and can make us safer. 

And, in the rare case when we know those involved, we might just openly ask them what happened. Then we can review their team communication, trip planning process, terrain-use mindset, the terrain they planned to avoid, and where they would have regrouped in the field to reflect, reassess, and adjust their plan.

I’m guessing that those who had the misfortune to suffer through the avalanche in the report would support us—and hope we can learn from their accidental event.


Colin Zacharias is a consultant and educator in the avalanche and mountain guiding industries, and an IFMGA/ACMG mountain guide. He resides on Vancouver Island.

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