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.
ahanna,
Avalanche Canada
As the wind picks up, fresh reactive wind slabs are likely to form at upper elevations. Great riding can still be found in sheltered, low elevation terrain thanks to the chilly temps!
Summary
Confidence
Moderate - Uncertainty is due to the speed, direction, or duration of the wind and its effect on the snowpack.
Weather Forecast
Sunday night: Clear. Light northwest wind. Treeline temperatures -18 C.
Monday: Increasing cloud with flurries starting. Wind increasing to strong northwest. Treeline temperatures around -13 C.
Tuesday: Flurries overnight then clearing. Strong northwest wind. Treeline temperatures around -10 C.
Wednesday: Increasing cloud. Strong northwest wind. Treeline temperatures around -8 C.
Avalanche Summary
No new reports of avalanche activity over the weekend. Avalanche activity on Thursday and Friday was predominantly small loose dry, size 1-1.5, observed out of steep terrain at treeline. On Thursday, evidence of natural storm slab avalanches size 2-2.5 were observed out of north facing alpine terrain.
Snowpack Summary
With plenty of soft, light snow available for wind transport, we expect to see wind slab formation at upper elevations as winds pick up on Monday. A northwesterly wind direction means atypical cross-loading and reverse loading patterns are likely.
20-40 cm now sits over a freezing rain crust below 1500 m and above this elevation it may rest on a layer of large surface hoar crystals. Our field team reported easy shears on this layer in their MIN report from during the storm on Wednesday but we're uncertain as to whether this layer remains a problem. You can see photos of the surface hoar prior to being buried by the storm in these MIN reports from Elk Mountain on Monday and Mt Kitchener on Tuesday.
A crust-facet sandwich formed in early December can now be found a meter deep. These layers show limited reactivity and are well bridged by strong snowpack layers above them. Below, the snowpack is generally well-settled.
Terrain and Travel
- Pay attention to the wind, once it starts to blow fresh sensitive wind slabs are likely to form.
- Wind slabs are most reactive during their formation.
- Avoid freshly wind loaded terrain features.
- Sheltered slopes at lower elevations will offer the best riding.
- Carefully assess open slopes and convex rolls where buried surface hoar may be preserved.
Problems
Wind Slabs
With plenty of soft, light snow available for wind transport, we expect to see wind slab formation at upper elevations (and possibly in open areas at lower elevations) as winds pick up on Monday. A northwesterly wind direction means atypical cross-loading and reverse loading patterns are likely.
Aspects: North East, East, South East, South, South West, West.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Dec 27th, 2021 4:00PM
