Avalanche Forecast
Issued: Mar 12th, 2021 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Loose Wet and Persistent Slabs.
kdevine,
Avalanche Canada
Rising freezing levels and sunshine will increase the likelihood of avalanches. Avoid exposure to cornices and steep sun-exposed slopes.
There is uncertainty about whether warming may wake up deeply buried weak layers, and uncertainty is best managed with conservative terrain.
Summary
Confidence
Weather Forecast
FRIDAY NIGHT - Mainly clear / light northwest wind / alpine low temperature near -2 / freezing level 1500 m
SATURDAY - Mainly sunny / light to moderate southwest wind / alpine high temperature near 2 / freezing level 2600 m
SUNDAY - Mainly sunny with increasing cloud in the afternoon / moderate to strong south wind / alpine high temperature near 1 / freezing level 2300 m
MONDAY - Mainly cloudy with sunny breaks / light northeast wind / alpine high temperature near -1 / freezing level 2100 m
Avalanche Summary
Rising freezing levels and sunshine will increase the likelihood of avalanches and cornice failures on Saturday. The potential for persistent slab avalanches may also increase with this weather pattern.
Reports from this week have mostly been limited to small wet loose avalanches on solar aspects, and small dry loose avalanches in steep, shaded terrain
During last week's warm weather, a large (size 2) slab avalanche released naturally on a weak layer of facets near the ground in a shallow snowpack area east of the region near Apex.
The most recent avalanche observed on the late January persistent weak layer was reported February 28th, when large explosives produced very large (size 2-3) results at Kootenay Pass.
Snowpack Summary
Wind slabs may be found in lee features at upper elevations. Soft, dry snow exists in sheltered, shaded areas. Solar aspects have a crust on the surface, which will become moist/wet with exposure to sunshine and rising freezing levels.
Deeper in the snowpack, a persistent weak layer from late January is buried 80-150 cm deep and is composed of a combination of surface hoar, crusts, and facets. There is some uncertainty about whether or not this problem will become reactive with rising freezing levels and solar radiation.
As described in this MIN report, shallow snowpack areas in the east of the region may harbor a faceted basal snowpack. This structure can typically be managed by avoiding shallow rocky areas where the snowpack transitions from thick to thin.
Terrain and Travel
- A moist or wet snow surface, pinwheeling and natural avalanches are all indicators of a weakening snowpack.
- Avoid steep slopes when air temperatures are warm, or solar radiation is strong.
- Minimize your exposure time below cornices.
- Be aware of the potential for large avalanches due to the presence of buried persistent weak layers.
Problems
Loose Wet
Warm temperatures and sunshine are expected to create prime conditions for wet loose avalanches. Solar aspects are the most likely trigger areas, but warm temperatures could potentially cause avalanches on all aspects.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Persistent Slabs
Persistent weak layers that were buried in January and February could become reactive again with intense solar radiation and high freezing levels.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Mar 13th, 2021 4:00PM
