Avalanche Forecast
Issued: Dec 16th, 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,
Cool alpine temperatures and short days call for early starts and extra warm layers.
Summary
Weather Forecast
A ridge of high pressure on Friday will give way to a weekend frontal system bringing snow to our region.
Tonight: Clear with cloudy periods, Alp temp -19*C, light NW winds
Fri: Mix of sun and cloud, Alp high -12*C, light SW winds
Sat: Periods of snow, 18cm, Alp high -12*C, mod SW winds
Snowpack Summary
Cooling temperatures will facet the new snow from the start of the week and break down wind slabs. Lingering wind slabs created by weekend extreme S'ly winds exist in exposed, Alpine and Tree-line features. These will be buried by ~15cm of loose dry snow. The Dec 1 crust is ~10cm thick at 1900m, buried by ~1m and found up to 2300m
Avalanche Summary
No new natural avalanches were observed along the highway corridor on Thursday, visibility was limited.
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.
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.
- 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
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 17th, 2021 4:00PM
