More Snow at Lake Louise, More Runs OpenPosted: December 30, 2010
A few days late for Christmas but welcome nonetheless, Lake Louise received some more snow over the last few days, improving conditions and allowing avalanche control teams to prepare more terrain for opening. At our Pika weather station, sensors recorded a total of 14cm, but depths up to 20cm were reported higher on the mountain and in wind loaded areas. At the same time, in a season where we’ve already seen a few instances of wind coming from the northeast, it happened again.
What does a northeast wind mean? Most of the time, Lake Louise gets southwesterly winds, resulting in fairly predictable loading patterns. In other words, southwest winds deposit wind-blown snow on the leeward northeast slopes. Lake Louise skiers know how much wind can improve areas like Boomerang and Whitehorn I & II, and avalanche control teams are good at predicting what avalanche conditions they’ll find after seeing recent wind and snow data. So, in short, southwest winds are why the front side of the Lake gets less snow than the back side – the wind picks up loose snow as it accelerates up the windward slopes, then dumps it on the leeward sides as it slows down and loses its ability to carry snow.
When winds come from the northeast, the loading patterns get reversed, and areas that usually benefit from loading get scoured, and vice versa. We saw these winds go into the 30km/h range, and while not strong enough to significantly change things, they did scour the tops, or start zones, of windward slopes. A good place to see how this affects a normally wind loaded slope is Rodney’s Ridge. For those travelling Saddleback, a quick peek over into Rodney’s Ridge/North Face will reveal scouring in the first few turns of the run, all along the ridge. The bulk of the slopes were not significantly affected, but stronger and more sustained winds could easily reach further down onto the slope itself.
Today, avalanche control teams are working in the Corridor/Crow Bowl/East Bowl areas, setting up fences and performing the last few rounds of control work before opening the terrain. Because the Corridor accesses the rest of the runs in that area, and is a long wind-exposed ridge, crews need to make sure that entry into the runs has not been too adversely affected by the northeast winds. With a little more snow, these areas will be ready to open.
In the overall snowpack picture, the colder than normal temperatures and shallower than normal snowpack has promoted the formation of hoar crystals, which are weak and offer little to no support for overlying snow. Once established these weak layers tend to stay around for the bulk of the season. Control teams are always working to flush these weak layers off of slopes, so that any future snowfall will have a chance to stay on the slope and form a stable foundation for the remainder of the season.