Dec 27, 2024 Conditions Report with Mitch Sulkers

Variability (...and uncertainty)

Last week I wrote about the concept of “layers”, with particular concern for the series of storms forecast to hit the Sea-to-Sky, and the legacy each might leave for our backcountry snowpack. As it turns out, it was an active week, and what stands out for me–as I answer questions regarding where to go and what to watch out for–is the variability to be found in the Sea-to-Sky at this moment in time and the uncertainty that this brings to the decision maker

There are a number of lenses one might consider when planning for the backcountry this week: best places to ski or ride and take advantage of the fresh snow; best places to reduce the obvious avalanche danger; best approaches to moving into the backcountry when the past week and forecast week are highly variable in their predictions for temperature, snowfall, and wind.

Currently, the best riding is taking place in a narrower elevational band from treeline down into the upper below treeline where there is sufficient base. Windspeeds well over 130kph during some of the storms have created a complex avalanche problem in the alpine and open areas of treeline. As winds changed direction and speed, significant windslabs were created on a variety of aspects, but as one descends from treeline, the storm snow is less wind-affected and better for riding

A problem that exists at this treeline/below treeline elevation is the presence of some crusts within the upper snowpack. Avalanches to size three suggest that in areas, the December 7th melt-freeze crust and associated facet layer could still be a concern, although it can be down as far as 180cms: more active is the December 22nd melt-freeze crust and some associated light layers of good winter snow just above it. This boundary between layers has resulted in a number of large avalanches this week, and likely contributed to many during the most recent Christmas/Boxing Day storm.

This problem is compounded somewhat in the Sea-to-Sky in that more coastal areas saw significant temperature fluctuations and heavier precipitation with lowering freezing levels during much of the most recent snow, while inland areas, like the Duffey, received much less, but much lower density snowfall. And even in the western Cayoosh of the Duffey, much of this snow fell on top of a melt-freeze crust at treeline and below.

For the moment, it looks like the best riding will be in the upper levels of the Below Treeline zone in areas where there is a sufficient base, especially from Whistler north. This area should also be easier to assess avalanche potential, as the prevalence of windslabs should be less. One must still consider the storm slab left by the most recent storm, however, and its bond with the layers beneath

This suggests more moderate slopes, below treeline, as a good start for getting familiar with our current problems. As the week progresses, this is going to be a dynamic problem, as several more storms, sometimes separated by a short window of clearing and fluctuating freezing levels, are forecast, and each will likely add another layer to the snowpack and the decision-making process as we venture into the backcountry.

There is good riding to be had, but everything points to the importance of keen and careful observation of the avalanche potential as one heads out into the Sea-to-Sky mountains this week. Start your days with as much knowledge as possible from the Avalanche Canada bulletins and other sources, and cautiously explore the area you are entering with a healthy dose of uncertainty. That is, quite simply, the name of the game this week…

Mitchell Sulkers

Extremely Canadian