Avalanche Forecast
Issued: Dec 25th, 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.
ahanna,
Avalanche Canada
Wind slabs remain the chief concern. Keep your guard up at lower elevations where wind slabs may be sitting over a weak layer.
Summary
Confidence
Weather Forecast
Saturday night: Partly cloudy. Light to moderate northwest wind. Alpine temperature around -22 C.
Sunday: A mix of sun and cloud. Light to moderate northwest wind. Alpine temperature rising to -15 C at through the day.
Monday: Overnight flurries up to 8 cm then clearing. Strong northerly wind. Alpine temperature around -10 C.
Tuesday: A mix of sun and cloud. Strong northerly wind. Alpine temperature around -13 C.
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.
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.
Snowpack Summary
Surfaces are extensively wind effected throughout the region. Exposed windward alpine and treeline terrain has been scoured to ground in places such as Paddy Peak and Powder Valley, with wind affected snow found well down into treeline. In the White Pass, firm wind slabs exist on south aspects and east facing gully features. Softer snow may still exist in sheltered treeline areas.
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 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
- Keep your guard up at lower elevations. Wind slab formation has been extensive.
- Watch for areas of hard wind slab on alpine features.
- Avoid slopes that sound hollow or drum-like.
- Back off if you encounter whumpfing, hollow sounds, or shooting cracks.
- Avoid shallow, rocky areas where the snowpack transitions from thick to thin.
Problems
Wind Slabs
Wind slabs may remain reactive at lower elevations where they sit over a layer of surface hoar. 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 drum-like sounds or cracking.
Aspects: East, South East, South.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Deep Persistent Slabs
Although the crust associated with this layer has largely decomposed, 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, try to think in terms of consequences just in case of a surprise. "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 26th, 2021 4:00PM
