Avalanche Forecast
Issued: Dec 26th, 2021 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs.
astclair,
Avalanche Canada
Northerly outflow winds are creating reactive wind slabs in unusual patterns. Keep in mind that cold temperatures can increase the consequences of an incident. Start simple, gather information as you go, and seek out softer conditions in wind-sheltered areas.
Summary
Confidence
Weather Forecast
Cold, Arctic air and north winds take the reins
Sunday night: Partly cloudy, no new snow expected, light northeast winds, treeline low temperatures near -16 C, freezing level at sea level.
Monday: Increasing cloudiness, no new snow expected, winds becoming northwest and increasing to moderate, treeline high temperatures near -12 C, freezing level at sea level.
Tuesday: Mainly clear, a trace of new snow possible overnight, moderate northwest winds, treeline high temperatures near -8 C, freezing level at sea level.
Wednesday: Mix of sun and cloud, no new snow expected, moderate northwest winds, treeline high temperatures near -8 C, freezing level at sea level.
Avalanche Summary
It remains possible to trigger to avalanches where the recent snow has been drifted into reactive slabs, especially near ridge crests and roll-overs.
On Sunday, backcountry travelers near Brockton Point reported a small pocket releasing in the storm snow on a steep terrain feature. On Saturday, operators reported small (size 1) soft slabs releasing in the storm snow from ski cuts that ran fast and far on a rain crust.
On Friday, we received several reports of touchy conditions in the North Shore Mountains. Check out these MIN reports from Hollyburn, Pump Peak, Brockton Point and Brockton Point for great descriptions and photos of the conditions.
Snowpack Summary
Since Friday, 25-40 cm of snow has fallen a variety of previous snow surfaces, including preserved powder and wind-packed snow at upper elevations and a rain crust near and below treeline.
Moderate to strong outflow winds at all elevations have had an ample supply of light, cold snow to drift into reactive slabs. Watch for unusual cross-loading or reverse-loading patterns in wind-exposed areas, and anticipate reactive wind slabs on a variety of aspects and potentially at lower elevations. Sensitivity to triggering will be greatest near ridge crests and roll-overs. Monitor for changing slab conditions as you move into wind-exposed terrain.
In the north of the region, a concerning layer of facets (sugary snow) can be found down 100-200cm over a crust that formed in early December. This layer is slowly transitioning from stubborn to unreactive as the snow above stiffens and makes it harder to trigger. This problem is particularly hard to predict and tricky to manage. Get more details and photos in our forecaster blog, and be sure to watch this week's snowpack summary video from North Shore Rescue.
Terrain and Travel
- Avoid freshly wind loaded features, especially near ridge crests, roll-overs and in steep terrain.
- Recent wind has varied in direction so watch for wind slabs on all aspects.
- Keep your guard up at lower elevations. Wind slab formation has been extensive.
- Make observations and assess conditions continually as you travel.
Problems
Wind Slabs
Winds have shifted from south to north with an ample supply of light, cold snow to drift into reactive slabs. Watch for unusual cross-loading or reverse-loading patterns in wind-exposed areas, and anticipate reactive wind slabs on a variety of aspects. Strong outflow winds may form slabs in wind-exposed areas at lower elevations.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Dec 27th, 2021 4:00PM
