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 Wind Slabs and Loose Wet.
dsaly,
Avalanche Canada
As you transition from melt-freeze conditions to dry snow, lookout for wind-loaded pockets in lee features. And the possibility of wet loose avalanches will persist where snow is moist or wet.
Summary
Confidence
Moderate - Uncertainty is due to the timing, track, & intensity of the incoming weather system.
Weather Forecast
SATURDAY NIGHT: Increasing cloud and wet flurries / Moderate, southwest ridgetop wind / alpine low temperature -1 / Freezing level 1100 m.
SUNDAY: Cloudy with flurries; up to 10 cm / Moderate, increasing southwest ridgetop wind / alpine high temperature -2 / Freezing level 1400 m.
MONDAY: Snow; 30-45 cm / Strong, southwest ridgetop wind / alpine high temperature -2 / Freezing level 2100 m.
TUESDAY: Snow and flurries; 10-15 cm / Moderate, gusty southwest ridgetop wind / alpine high temperature -2 / Freezing level 2000 m.
Avalanche Summary
No new avalanches were reported on Thursday or Friday, however pinwheeling on steep south and west aspects was reported.
Last Wednesday, a natural widespread wet loose avalanche cycle up to size 3 occurred. A cornice failure size 1.5 also occurred triggering a small surface slab on the slope below.
Have you been out and about in the mountains? If so please submit to the Mountain Information Network (MIN). It doesn't have to be technical it can be as simple as a photo. Photos are especially helpful! Sending out a big thank you to the already submitted MIN's this season. Thanks everyone!
Snowpack Summary
Recent sun and warm air well into the alpine had the greatest impact on the upper snowpack. A melt-freeze crust is found on most slopes. At upper elevations on more shaded slopes where dry snow prevails, wind slabs have formed in lee features. Surface hoar growth has been observed in sheltered areas at treeline and below.
The snowpack depth varies with elevation. Below treeline 30 to 70 cm, 80 to 100 cm near treeline, and around 150 cm may be found in the alpine.
The mid to lower snowpack contains a series of crusts, the most notable of which is also the deepest, sitting just above the ground at elevations above 1500 m. This crust may have a thin overlying layer of weak faceted grains and/or surface hoar crystals, especially in sheltered areas around treeline. There is uncertainty as to whether these layer will be a concern going forward.Â
Terrain and Travel
- Approach lee and cross-loaded slopes with caution.
- Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
- Avoid steep slopes when air temperatures are warm, it is raining, or solar radiation is strong.
- Back off slopes as the surface becomes moist or wet with rising temperatures.
Problems
Wind Slabs
Recent strong southerly winds have likely redistributed dry snow at upper elevations, look out for rogue pockets of wind slabs in lee features and below ridgelines. Expect new slabs to form as the incoming storm brings new snow and wind.
Aspects: North, North East, East, West, North West.
Elevations: Alpine.
Likelihood
Expected Size
Loose Wet
The wet-loose problem will remain in areas where the snowpack is not frozen and/or rain saturates the snowpack.
Aspects: South East, South, South West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Dec 6th, 2020 4:00PM
