Avalanche Forecast
Issued: Nov 29th, 2022 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs.
zryan,
Avalanche Canada
Be cautious as you transition into wind-affected terrain. Easterly outflow winds have started to form fresh wind slabs in unusual areas and at lower elevations than is typical.
Cold temperatures, short days, and early season hazards should factor into your trip planning. Be prepared for an emergency and leave yourself plenty of daylight to get home safely.
Summary
Confidence
Moderate
Avalanche Summary
During last week's storm, a natural avalanche cycle occurred with notable very large avalanches (size 3) failing in wind-loaded terrain.
As northeasterly outflow winds increased on Monday night, operators in the north of the region reported several small (size 1) natural wind slabs from steep terrain.
Looking forward to Wednesday, we expect easterly winds to continue to form fresh wind slabs on south and west-facing slopes. These wind slabs will be in more atypical areas that are usually windward, which may take riders by surprise.
Snowpack and avalanche observation data are currently very limited in this region. If you head out in the backcountry, please consider posting your observations to the MIN. (Mountain Information Network)
Snowpack Summary
Last week's storm delivered 70-150 cm of new snow accompanied by very strong southwest ridgetop winds.
Over the past 2 days, strong easterly outflow winds and cold temperatures have started to stiffen the upper snowpack and strip wind ward, easterly aspects. In areas where the storm snow remains loose and powdery, these winds may redistribute it into fresh windslabs.
This storm snow overlies a hard old surface created during the mid-November cool period. This layer consists of a crust below ~1200m and a layer of surface hoar, which has been found primarily in isolated, protected terrain. This layer has not shown any alarming reactivity at this time.
The depth of the snowpack at treeline varies widely from 100-200 cm and tapers rapidly below treeline.
Many early-season hazards such as rocks, stumps, and open creeks exist below treeline.
Weather Summary
Tuesday night
A mix of sun and cloud. Easterly outflow winds increasing to 50-90 km/h. Temperatures dropping to -25 C at treeline.
Wednesday
Mainly sunny. Easterly winds 40-80km/h. High temperature at treeline -22 C.
ThursdayPartially cloudy. Light variable winds. Temperatures rising, high temperature at treeline -13 C.
FridayA mix of sun and cloud. Easterly winds 40-60km/h. High temperature -12 C at treeline.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
- Recent wind has varied in direction so watch for wind slabs on all aspects.
- Avoid steep, rocky, and wind effected areas where triggering slabs is more likely.
- Use ridges or ribs to avoid areas of wind loaded snow.
Problems
Wind Slabs
Easterly winds may form fresh wind slabs on south and west-facing slopes that are typically more windward.
Watch for for lingering, older wind slabs formed by the strong southwest winds that accompanied the storm ending last weekend. These slabs are likely becoming quite stubborn to trigger in many areas.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Nov 30th, 2022 4:00PM
