AVALANCHE, POOR POSITION, FAILURE TO TEST CONDITIONS, RELYING ON OTHERS
Alaska, Delta Range, Castner Glacier
In the early afternoon on March 1, a group of 17 people (15 class members, co-leader Ty Humphrey, and I) arrived on skis and snowshoes in an area with ice cliffs for practicing crevasse rescue in the lower section of the Castner Glacier. I arrived first and found a suitable ice cliff. This ice cliff was located underneath a moraine slope of about 100 feet and the angle of about 35 degrees. The snow on the slope was about thigh deep, mainly sugar snow with a thin slab on top of that.
Being accustomed to the false idea that the moraine slopes on the Castner Glacier are not long enough to accumulate sufficient amount of snow that could create an avalanche of a concerning magnitude, we neglected to give the situation a deeper thought and started setting up anchors at the upper edge of the slope without testing the snow on the slope for stability. The anchors (“dead men” made from skis) were set up in a lower angle (~25 degrees) section of the slope close to the upper edge of the slope and combined with an anchor formed by a rope going around a big rock in a flat area above the slope’s edge.
I was the first one to rappel down the slope and the ice cliff. I was just about to unclip from the rope when I heard an avalanche. At first I thought the avalanche was on one of the distant mountain slopes, but it didn’t take me too long to figure out that it was actually on the slope above me and coming right on me. Even though I tried to swim, my feet got caught in the packed snow and I got partly buried, with my head, hands, and part of my chest sticking out after the snow movement completely stopped. The only other person affected by the avalanche was Eamon. He was at the upper edge of it when the snow came loose and he ended up riding down with it. After flying down the ice cliff, he supposedly had a relatively soft landing on top of the avalanche debris. Soon after that, Eamon was delivered a shovel and he dug me out from the snow. Nobody was hurt.
Looking at the slope above the ice cliff, it was now pretty much free of snow up to the upper edge of the steep slope section. It ended right below the anchors that were in the lower angle section. The surface was ice and small rocks. The avalanche was most likely triggered by our activity at the upper edge of the steep slope section.
After a short discussion with the class about the mistakes we made, we redid most of the anchors; we placed some of them into the flat area above the slope’s edge and made ice-screw anchors on the slope, which now was free of snow and allowed us to find rock-free areas for ice screws. The slope clear of snow and the ice cliff underneath were now safe to practice crevasse rescue. The rest of the course went normally.
My mistake was acting automatically (choosing a similar slope and ice cliff as the last year and the year before) and not using enough thought in action. I should have initiated a snow stability test. Especially since this was a class, we should have spent a good amount of time on analyzing the conditions (pit, layers, compression test, angle estimate, etc.) and reviewed the students’ avalanche knowledge.
The mistake of others was not thinking for themselves and relying on my thinking. They should have questioned whether what we were doing was safe. Nobody voiced any concern.
How do we learn from this?
Prevent acting automatically. Think of what you are doing.
Be self-sufficient; think for yourself and don’t rely on thoughts of others. Safety is everyone’s responsibility.
Even relatively short moraine slopes can pose an avalanche danger. Test the slopes before you use them.
Should we carry beacons on the Castner Crevasse Rescue Course? One of the questions asked by students at the planning meeting before the trip was whether they should have beacons. My answer was that they don’t need beacons because we won’t be in an avalanche prone area. I encouraged them to have shovels and probes, though (even though at that time I mainly meant it for camping and testing crevasses).
Next time, I still wouldn’t require the participants to have beacons, but I would at least recommend them. I think most years we will be able to eliminate avalanche danger by proper selection of ice cliffs to practice on. But good cliffs are scarce and it can sometimes happen that the only suitable ice cliff will have an avalanche slope above it. Beacons could be useful in that situation. I still don’t see them as a necessity, though, because we are talking about small avalanches and chances are high that people won’t get completely buried and if they do, chances are high that even without beacons they will be quickly found,
given the number of people around and given the relatively small area covered by the avalanche. (Source: Tomas Marsik, age unknown)