More Snow at Lake LouisePosted: November 10, 2009
Contrary to the local weather forecasts we looked at yesterday, it’s currently snowing heavily at Lake Louise, with a few cm’s already on the ground. Added to the 25cm or so we received over the weekend, things are looking good for more lift and run openings later this week. Avalanche control and trail crew teams have done a good job of traveling around the mountain and compacting the snow as much as possible, either by explosives use, ski cutting, or side-stepping on drifts.
Disturbing the snow goes a long way in slope stabilization, as the layers in the snowpack are interrupted, and the disturbed snow settles in firmer than it was before. On avalanche slopes, ski cutting has the dual benefit of compaction and cutting up a large slab into smaller pieces, reducing the likelihood and consequences of avalanches.
As the avalanche control team moved through Saddleback a few days ago, they remote-triggered an avalanche that started mid-slope of Whitehorn I. It ran on a weak layer of facets, formed at the bottom of the snowpack when we had those unseasonably cold temperatures in October. In other locations, teams were experiencing a lot of ‘whoomphing’, which is the term used to describe when a weak layer in the snowpack collapses, and the air trapped inside the snowpack rushes to the surface in an audible ‘whoomphing’ sound – hence the name. Whoomphing tends to happen on flatter terrain, where the slope isn’t steep enough for the snow to avalanche, but the weak layer still exists and can collapse nonetheless. On steeper terrain, the collapse of the layer generally results in an avalanche, provided there is sufficient snow on top of the layer to run.
The photo below shows the avalanche in Whitehorn I. Remote-triggering refers to an avalanche that starts away from where the load was placed on the snowpack. What likely happened is the weight of the skier(s) caused a whoomph, which has the ability to propagate under the snow and travel along the weak layer for considerable distance, in this case running up slope until it hit a weak spot on the slope (around boulders perhaps) and causing an avalanche. The ski track in the photo is where the team was when the avalanche released.
Finally, because you can never have enough shots of Boomerang in its undisturbed glory, here’s a shot taken yesterday from the top of Paradise chair.