2023-01-18 Conditions Update

Looking Back:

-Super late fall. Totally dry through end of October and into November before we had a low moisture start to the winter. When it did start snowing, it was cold, dry, and not much snow.

-Thin initial snowpack through Nov and Dec.

-Surface hoar layer of concern in Nov and Dec at treeline, especially north of Squamish.

-Basal facets and depth hoar developing with cold temps (just before Xmas) and thin snowpack.

-Cold period of high pressure then cold with précip mid-December followed by big warmup over Christmas. This created the Xmas crust.

-Somewhat consistent snowfall on this crust throughout the corridor (50-80cm?).

Current:

-generally a period with limited actual observations! Low tide on glaciers (crevasses)!

-Snow accumulating on the Xmas crust. 50-80+ depending on where.

-last warmup period fully saturated the BTL snowpack, which is still isothermal in some places. Especially North Shore and Squamish.

-1700m -2100m saw rain fall at the peak of the storm. Created a mid-Jan crust layer.

-Above 2100m, further north, saw little or no rain and therefore no crust formation (in these areas, snow is still loading on the Xmas crust). This creates a much more serious storm slab issue as the slab is >80cm thick in places!

-Since last weekend’s warmup, snow has been falling again with 20-40cm of HST as of yesterday and probably another 10-20cm today.

Looking forward:

-a trickle off of storms, maybe some colder weather. Then high pressure on the horizon. If it’s not too cold, I’m hopeful it will help settle!

-I’m going to be hesitant around high alpine features until I have some more observations. For now, sticking to supported and fat features, ideally ones I know slid in the storm. Not trusting of unsupported/convex or shallow/rocky features - perfect for triggering storm slab on near surface facets!

Questions:

-Will the xmas crust act as a PWL, especially at higher elevations where mid-Jan crust didn’t form?

-Will older SH layers or basal facet layers wake up in spring and cause problems?

What will I be doing?

-How deep is either the mid Jan or Xmas crust buried?

-How well bonded/settled is the new snow? It will start as a storm slab (today) but hopefully will settle quickly with forecast temps. Wind slab will be the main issue.

-Check the public bulletin! Especially the AVALANCHE PROBLEM. These really tell you what you need to know and the terrain to avoid.

-Post a MIN on avalanche Canada!

-the current snowpack is a bit weird but it’s not game over. Lots of good skiing to be found! We just have to think a bit more.

-Use the custom shading in FATMAP! We’ve found the best skiing generally between 1700 and 2000 m on sheltered aspects. You can punch that into Fatmap and get exactly where to go overlaid on the map! Same goes for avalanche problems!