Avalanche Forecast
Issued: Dec 24th, 2021 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs and Deep Persistent Slabs.
TRettie,
Avalanche Canada
Make conservative choices and leave plenty of time to get home safely. Cold temperatures will make any accident more consequential.
Summary
Confidence
High -
Weather Forecast
Friday night: a possibility of light flurries. Moderate to strong wind from the north with a Low of -28.
SATURDAY: High of -27 at 1200m. Moderate ridgetop winds from the north. No new snow expected.
Sunday: temperatures rising to -14 at 1200m throughout the day. moderate north winds becoming moderate southwest. Flurries in the afternoon.
Monday: up to 10cm of new snow expected with moderate southwest winds. high of -16 at 1200m.
Avalanche Summary
On Wednesday our field team observed several natural avalanches up to size 2 on Log Cabin and above Fraser Chutes. These avalanches were on cross-loaded east and south east facing slopes above treeline.Â
The most likely place we will see avalanche activity will be on south through east facing slopes where wind slabs have not yet bonded well to the layer below due to cold temperatures.Â
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Snowpack Summary
In general little snow is left for transport but cold temperatures will continue to promote surface faceting. These faceted crystals could serve as new snow for transport and wind slab development.
Exposed alpine and treeline areas in places such as Paddy Peak and Powder Valley have been scoured to ground on north aspects and ridges. Wind impacted snow also exists well down into treeline in these places.
In the White Pass, all but sheltered, south facing slopes have been impacted by the wind. Firm wind slabs exist on south aspects and east facing gully features. Softer snow does still exist in sheltered treeline areas.Â
Surface hoar exists just below the surface at 1300m and below. It is likely only a problem where wind slab has formed above it.
The middle snowpack is supportive to travel but snow depth still varies greatly with aspect and elevation.Â
The lower snowpack is made up of weak sugary snow. An avalanche at this interface is most likely to be triggered in shallow areas or with a large impact like a cornice fall or surface avalanche.
Terrain and Travel
- Watch for areas of hard wind slab on alpine features.
- Seek out wind sheltered terrain below treeline where you can avoid wind slabs and find great riding.
- Keep your guard up at lower elevations. Wind slab formation has been extensive.
- Avoid shallow, rocky areas where the snowpack transitions from thick to thin.
Problems
Wind Slabs
At the moment, there may be a temptation to ride in areas where the snow has been deposited by the wind. Be aware that in these areas wind slabs could remain reactive longer than usual due to the extremely cold temperatures. Keep in mind that firm slabs can be triggered farther down slope than you might expect. Don't get surprised! As you transition from sheltered areas into wind affected areas, pay attention to ski and track penetration and consider backing off if you encounter firm drum-like slabs or cracking. Sensitivity to triggering these slabs could also be greater where they have formed over surface hoar at lower elevations.
Aspects: East, South East, South.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Deep Persistent Slabs
Although the crust associated with this layer has all but disappeared, the weak sugary crystals at the base of the snowpack remain. The bridging affect of the wind hammered upper snowpack is making it harder to trigger this layer but now is not the time to become complacent. When managing hard slab on top of facets I try to think in terms of consequences just in case I get surprised. "If I trigger an avalanche here, what are the consequences? Will the avalanche be large? Are there terrain traps?"
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Dec 25th, 2021 4:00PM
