Avalanche Forecast
Issued: Dec 15th, 2021 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Persistent Slabs and Wind Slabs.
Catherine Brown,
Don't be surprised by the Dec 1st crust/persistent slab!
Approach steep and convex terrain with caution, especially at tree line.
Summary
Weather Forecast
Cooling temperatures, flurries and light winds over the next couple days. A frontal system will usher in weekend snow.
Tonight: Cloudy, Trace amounts of snow, Alp temp -13*C, light SW winds
Thurs: Cloudy with sunny periods and isolated flurries, Trace snow, Alp high -11*C, light/mod W winds
Fri: Mix of sun and cloud 4cm, Alp high -14*C, light W winds
Snowpack Summary
Cooling temperatures will start to facet the new snow from the start of the week and break down wind slabs. Look for wind slabs created by extreme S'ly winds on Saturday in exposed, Alpine and Tree-line features. These will be buried by ~15cm of loose dry snow. The Dec 1 crust is ~15cm thick at 1900m, buried by ~1m and found up to 2300m.
Avalanche Summary
On Wednesday, 5 artillery rounds produced 1, size 2 avalanche from a steep, N facing start zone off Mt. Macdonald.
A MIN report on Tuesday described a wind slab in the alpine on lee features reacting to a skier load.
We observed some natural avalanche, up to size 2.0 on Monday night and Tuesday trigged by new snow and strong winds.
Confidence
Problems
Persistent Slabs
The Dec 1st crust is buried by 40-80 cm of snow. Be especially cautious in thinner snowpack areas, where it is more likely to be skier triggered. The crust is most reactive at tree line, but it is present below tree line and in the lower alpine.
- Avoid steep convexities or areas with a thin or variable snowpack.
- Carefully evaluate terrain features by digging and testing on adjacent, safe slopes.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Wind Slabs
Extreme weekend winds have created wind slabs. Expect variable distribution of these slabs, from lee features to further down slope then expected. These slabs are buried by 15 cm of new snow.
- Be careful with wind loaded pockets, especially near ridge crests and roll-overs.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Dec 16th, 2021 4:00PM
