Slope Stabilization in Boomerang and BrownshirtPosted: November 13, 2010
Those skiing at Lake Louise early last season may remember that we experienced a widespread avalanche cycle in much of our alpine terrain, losing much of the snow that had fallen to date in places like Brownshirt and Whitehorn II. This was in part attributable to heavier-than-average November snowfalls, which made it difficult for avalanche control teams to get into every piece of terrain before everything slid.
With lower snowfall so far this year, control teams, with the help of other patrollers and the trail crew, have done a great job of getting to where the snow is and using a combination of ski packing and bootpacking to break up the weak layers and temperature crust that exist. All of this work contributes to stability of the slope, and helps ensure the snowpack builds the way we want it to, giving it the best chance to survive the season. With more snow forecasted to fall early this coming week, crews will be constantly working these areas to make sure all new layers of snow are packed in as much as possible. It’s a big job, with huge amounts of terrain to cover, but also with equally huge rewards for all.
Boomerang is a perennial early season performer, as it is a flat, shale-covered surface that receives near-constant wind-loading. It’s usually the first alpine run to be skiable, and therefore often receives the bulk of attention from control teams. On the way to Boomerang is Windy Gap, which can be a vexing place to get snow to stick. I’ve lost count of the number of different ways teams have come up with to get wind-blown snow to stay put. The challenge comes from the wind, which usually blows strongly and can come from any direction (this is why early season skiers may have noticed that the snow fence there sometimes lays in a bunch of zig-zag patterns, rather than in long straight lines like everywhere else on the mountain). In any case, we can’t miss any opportunities to pack down any snow that gathers there, or else run the risk of having it all blow away again. Every flake counts!
In Brownshirt, there’s enough snow for control teams to have begun ski-cutting, which is another slope-stabilization technique. Patrollers travel the run on skis, making big zig-zag tracks down the length of the run. This disrupts the continuity of layers, and breaks up what may be one big slab of snow on the slope into smaller pieces, reducing the likelihood and consequence of an avalanche. You’ll see these ski cuts in all of our avalanche terrain all season long, as it is the preferred method of avalanche control used by patrollers. In sketchier terrain, or when there’s more snow, patrollers will switch to the use of safer (and more expensive) explosives. Generally, frequent smaller dumps are easier to manage than occasional big dumps, which can slow things down as patrollers need to travel more slowly through hazardous terrain. Not that we ever complain about big dumps…