Avalanche Forecast
Issued: Nov 28th, 2018 4:45PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Storm Slabs.
jsmith,
Avalanche Canada
There is a high degree of uncertainty regarding the weak layer that is below this past week's storm snow. Where this nasty layer exists, human triggering may be likely. Conservative terrain choices are key during times of high uncertainty.
Summary
Confidence
Low - Due to the number of field observations
Weather Forecast
Overnight WEDNESDAY: Cloudy / Alpine Low -4 / Light to moderate, west wind / Freezing level 500 m.THURSDAY: Cloudy with isolated flurries / Alpine high -4 / Light, west wind / Freezing level 1000 m.FRIDAY: Cloudy / Alpine high -5 / Light, west wind / Freezing level 600 m.SATURDAY: Mix of sun and cloud / Alpine high -7 / Light, north wind / Freezing level 400 m.
Avalanche Summary
No avalanches were reported in this region on Tuesday. However, we currently have very few observations from within this region. Please post your observations to the Mountain Information Network (MIN). Although not in this region, a notable size 3, human triggered avalanche was reported in the South Columbia region on November 24th. The avalanche reportedly occurred on a northwest aspect, on a lee feature in the alpine and likely ran on a crust near the bottom of the snowpack. The full report can be found on the Mountain Information network. Click here to read the report
Snowpack Summary
Ongoing snowfall since Sunday night brings total recent storm snow amounts to 40-90 cm. This new snow sits on top of a weak layer of surface hoar (feathery crystals) and sun crust on steep south facing slopes. The surface hoar is most pronounced at treeline and below, but it may be found in sheltered alpine areas.At the base of the snowpack is a crust that formed in late October. There have been no reports of reactivity on this layer in the North Columbia region, however with recent snow, winds and high freezing levels, this layer could become active in isolated locations. Total snowpack depths vary greatly with elevation. Recent reports show depths of 120-210cm in the alpine, 80-150 cm at treeline and 10-120 cm below treeline.
Problems
Storm Slabs
Widespread storm slabs sit on a weak layer of surface hoar (feathery crystals), and sun crust on steeper south facing slopes. Expect to find deep deposits of snow over this layer in wind loaded areas.
If triggered, the storm slabs may step down to deeper layers resulting in large avalanches.Watch for signs of instability such as whumpfing, cracking, and recent avalanchesBe careful with wind loaded pockets, especially near ridge crests and roll-overs.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Nov 29th, 2018 2:00PM
