The Invisibility of Small Slopes

Ironically, while large avalanches in obvious avalanche paths undoubtedly kill some recreationalists, many avalanche fatalities occur on small slopes with no obvious path. Recognizing avalanche terrain is not as simple as some people think. Big paths with wide swathes cut through the trees and lots of flag trees are obvious avalanche paths to even the most novice winter recreationalist, while more subtle, but still potentially deadly avalanche terrain frequently goes unrecognized.

Last week, during the height of a storm that saw 50 cm of heavy snow deposited in 24 hours under strong to extreme winds with warming temperatures, one of our group went out by himself and broke trail up a short, steep NW facing slope that was sparsely timbered. He had been told by a more experienced member of our group that the route he was planning was "totally safe". After breaking trail up the short steep slope he entered a gully, then crossed through the run-out zone of a large avalanche path. All of this by himself with rapidly deteriorating stability during the peak of an avalanche cycle. When the visibility cleared somewhat, it was obvious that he had remote triggered a 90 cm deep avalanche on a 30 degree slope, that, as luck would have it, did not reach him.

A couple of weeks previously, a friend of mine, leading a group of four (including herself) when avalanche hazard was rated considerable, set the track across a steep cross-loaded slope with even steeper slopes above. A kick-turn was put in right below the steepest section of the slope. When the second member of the party was in the midst of the kick turn (an awkward and inescapable position), she remote triggered the slope above which buried the second and third members on the party, the second to the neck (with hands pinned down) and the third to the waist. The first member of the party ran to safety and was only brushed by the avalanche. The last member of the party, inexplicably, had no backpack (and thus no shovel).

In both cases, small avalanche slopes were either underestimated or completely unrecognized. Although I have no real proof, I suspect the latter, as, in both cases, safer options existed that would have avoided the slopes all together.

An avalanche professional once said "when the question is stability, the answer is terrain." A useful axiom, but only if you have the ability to recognize the avalanche hazard on small, non-obvious slopes, which clearly, many winter recreationalists - even very experienced ones - are unable to do. 

A small slope that released as I approached it