Buried!Posted: March 5, 2012
Well, we keep trying to come up for air here in Lake Louise, but it just keeps snowing and we’re just going to keep on holding our breath! All departments had their hands full on Sunday, and none more than the avalanche control teams, who were faced with lots of snow and lots of terrain to cover, with little visibility to allow them to see where they were going or the results of their control work.
Saturday night saw 21cm of snow fall at our Pika weather plot, and other than a few hours Sunday morning, it never let up. The avalanche control teams made their way onto the mountain, altering their plan of attack slightly since Top of the World (TOW) chair was not running. Once on the upper mountain, crews focused on the front side of Summit and TOW, then made their way around to Whitehorn I, Rodney’s Ridge, and the terrain off of the backside of Paradise chair. These are usually the first backside areas to receive control work, since once they’re done we can open Saddleback and give an option to those looking for a green run in the alpine.
With the main pieces of avalanche terrain opened, crews headed toward Whitehorn II. What they saw when they got there were accumulations in wind-loaded terrain of 35-40cm. This snow had been accompanied by winds that blew steadily in the moderate range (20-50km/h) and had gusts in the high range (50+km/h), so there was the expectation that slab conditions had developed and that avalanches would likely be easily triggered by ski cuts and explosives. With the snow still coming down and the wind still blowing, visibility was poor, and crews had to move slowly through the terrain to ensure their own safety.
One of the issues in Whitehorn II is that there are numerous micro-features. In other words, one must consider not only the main part of the slope when conducting control work, but also all the little areas that have their own loading characteristics due to terrain features (rock outcrops) and changes in aspect. This makes for nit-picky work, especially considering that wind-loading was ongoing, and tracks made on these slopes were quickly being filled back in. With all of these conditions making it difficult to make progress in controlling slopes, the decision was made to keep Whitehorn II, Boomerang, Brownshirt, and North Cornice closed for the day.
Which brings us to today, and another 17cm of new snow added by 6:00am this morning. A significant difference last night was that there was much less wind, so the result was lighter, non-wind-affected snow laying over top of slabbier, slightly heavier snow. We call lighter snow over heavier snow building “right side up”, which is what we want. The opposite is “upside-down”, where you have heavier snow laying over lighter, and avalanches are more likely in these cases. However, with all that terrain closed on Sunday, we did not get the skier compaction that we rely on so heavily for slope stability, so avalanche control teams this morning were faced with up to 55cm of new, uncompacted snow in many alpine leeward slopes. Visibility is no better, so teams are moving very carefully through the terrain trying to get it open. Whether those runs that remained closed yesterday open today remains to be seen. There’s a good chance that if this snow keeps up and we get what some forecasts are calling for another 20+cm, then any progress will be hard-fought and short-lived.
Either way, the next few days look like they’re going to provide no shortage of epic turns, and, by hook or by crook, the terrain will open eventually!