Avalanche Forecast
Issued: Dec 5th, 2020 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Deep Persistent Slabs.
ahanna,
Avalanche Canada
Find the best snow on shady, wind sheltered aspects. If you're getting sendy, check your line for rogue pockets of wind slab. Getting knocked off your feet can be serious in extreme terrain.
Summary
Confidence
Moderate - Uncertainty is due to the limited number of field observations.
Weather Forecast
Saturday: Clear, light southwest wind, temperature inversion breaking down, freezing level 800 m.
Sunday: Sunny, light southwest wind, freezing level 800 m in most areas, 1400 m in the south of the region.
Monday: Flurries, light southwest wind, freezing level 900 m.
Tuesday: 5-10 cm new snow, light southwest wind, freezing level 900 m.
Avalanche Summary
Loose snow avalanches up to size 1.5 were reported on steep solar aspects during the warmup on Wednesday and Saturday.
Check out this notable MIN report of numerous human triggered avalanches from Quartz Creek last weekend. The buried layer of small surface hoar that caused this avalanche could still catch riders by surprise.
Our eyes and ears in the mountains are limited this winter due to fewer professional observations. If you go out in the mountains, please share your observations on the Mountain Information Network (MIN). Photos are especially helpful! Thank you so much for all the great MINs submitted so far!Â
Snowpack Summary
A melt-freeze crust on steep solar aspects at treeline and above will soften through the day. On shadier aspects, alpine surfaces are predominantly wind affected, with soft snow still to be found in at lower elevations. Widespread growth of large surface hoar crystals and surface faceting have been reported. These types of crystals (crust, hoar, facets) that develop on the surface as it sits exposed during prolonged periods of high pressure like this often become a problem once buried by the next snowfall.
The lower snowpack is characterized by a couple of crusts, the most notable of which is sitting near the base of the snowpack, likely surrounded by a weak layer of sugary facets. It is most likely to be reactive to human triggers on south facing slopes and in shallow, rocky areas in the alpine.
Terrain and Travel
- When a thick, melt-freeze surface crust is present, avalanche activity is unlikely.
- Be alert to conditions that change with aspect and elevation.
- Small avalanches can have serious consequences in extreme terrain. Carefully evaluate your line for wind slab hazard before you commit to it.
Problems
Deep Persistent Slabs
So here's the story... A crust sits near the base of the snowpack.
On the one hand, there hasn't been any associated avalanche activity in weeks.
On the other hand, it's surrounded by weak crystals and still producing hard results in snowpack tests.
Although we don't think it presents an avalanche problem under the current conditions, we're reluctant to throw it out altogether, especially with new snow on the horizon. If it were to rear its head, it would most likely be in shallow, rocky areas in the alpine.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Dec 6th, 2020 4:00PM
