Avalanche Forecast
Issued: Dec 14th, 2021 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs and Persistent Slabs.
Chris Gooliaff,
Cool temps will slowly soften surface slabs.
Be wary of areas where the snow feels dense or stiffer. These slabs may be sitting upon a smooth, hard crust, waiting for a human trigger.
Summary
Weather Forecast
A mixed bag over the next few days, with scattered flurries and moments of sunshine.
Tonight: Cloudy, Trace amounts of snow, Alp temp -13*C, light SW winds
Wed: Cloudy with sunny periods and isolated flurries, Trace snow, Alp high -12*C, light SW winds
Thurs: Mainly cloudy with scattered flurries, 4cm, Alp high -12*C, light W winds
Snowpack Summary
15cm of fluff Monday night has covered the weekend's fresh slabs, created by extreme S'ly winds Saturday. These slabs were prevalent in exposed, Alpine and Tree-line features, further downslope than normal. The Dec 1 crust is ~15cm thick at 1900m, buried by ~1m and found up to 2300m. The mid and lower snowpack is generally well bonded and strong.
Avalanche Summary
Natural and human triggered avalanche activity has decreased since the weekend.
Reports of denser surface snow below tree-line is indicative of settlement, which can produce a cohesive slab that fails as one unit. Given the Dec 1 crust is most prevalent below tree-line, this hard surface could be the perfect sliding layer for the slab to move on.
Confidence
Problems
Wind Slabs
35cm of new snow over the weekend was redistributed by extreme winds (up to 140km/h at Mac West Shoulder wx station Sat!). These extreme wind events may create slabs where you would not normally expect them. 15cm of new snow has hidden these slabs.
- Be careful with wind loaded pockets, especially near ridge crests and roll-overs.
- If triggered the wind slabs may step down to deeper layers resulting in large avalanches.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Persistent Slabs
There is 50-90cm on the Dec 1st crust (a very hard, smooth layer for slabs to slide on), which has been skier-triggered in thinner snowpack areas. It is mainly an issue at tree-line, but also extends into the lower alpine up to 2300m.
- Carefully evaluate terrain features by digging and testing on adjacent, safe slopes.
- Avoid steep convexities or areas with a thin or variable snowpack.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Dec 15th, 2021 4:00PM
