Avalanche Forecast
Issued: Dec 1st, 2018 3:45PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Storm Slabs.
swerner,
Avalanche Canada
With few field observations, uncertainty exists around the buried weak layers in the snowpack. Natural avalanche hazard has tapered off but human triggers are still possible, especially where the slab sits above a weak layer. Forecaster BLOG here.
Summary
Confidence
Moderate - The weather pattern is stable
Weather Forecast
As the upper ridge sets up we will move into a period of cooling, drying and fairly light, northerly winds. SUNDAY: Mix of sun and cloud/ alpine temperatures near -5/ generally light winds from the northeast/ freezing level 1100 mMONDAY: Cloudy/ alpine temperatures near -10/ ridgetop winds light from the northeast/ freezing levels valley bottomTUESDAY: Mix of sun and cloud/ alpine temperatures -12/ ridgetop winds light from the southwest/ freezing levels valley bottom.
Avalanche Summary
Several small human triggered storm slabs up to size 1 were reported on Saturday. Even though the avalanche hazard has decreased I suspect human triggered avalanches will be possible, especially where the storm slab sits above a weak layer like surface hoar or the early November crust. If you're in the backcountry and have observations to share, please post to the Mountain Information Network.
Snowpack Summary
Another 7 cm of snow overnight adding to the 55 cm of recent storm snow that fell earlier this week. Recent south and southwest winds have formed pockets of wind slab on leeward terrain, however the winds have switched to a northerly direction and are potentially redistributing the new snow on opposite. slopes. Below the surface exists a series of crusts and a feathery surface hoar layer. We have a lot of uncertainty around this weak layer, its distribution is spotty. I suspect it could exist on sheltered slopes in the alpine and at treeline. Deeper in the snowpack a melt-freeze crust exists at treeline and into the alpine on all aspects. Reports indicate that the slab above this crust may be more reactive on northeasterly aspects. I would investigate this bond before jumping onto large, planar terrain features. At the bottom of the snowpack you'll likely find melt-freeze crusts and sugary weak facet crystals. At treeline the average snowpack depths are 80 cm. These depths taper rapidly at lower elevations.Check out the new forecaster blog post "The Buzz". Discussing uncertainty with what lies beneath...
Problems
Storm Slabs
Storm slabs may be more reactive to human triggers where they are stiffer from wind effect and/or sit above a weak interface like surface hoar or a crust.
If triggered the storm slabs may step down to deeper layers resulting in large avalanches.Watch for signs of instability, such as whumphing, shooting cracks, and recent avalanches.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Dec 2nd, 2018 2:00PM
