Avalanche Forecast
Issued: Feb 27th, 2021 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs and Persistent Slabs.
kdevine,
Avalanche Canada
Watch for changing conditions as strong winds may mean that wind slabs become increasingly reactive throughout the day. Avoid overhead hazard during times of rapid loading due to strong winds.
There is the potential to trigger deeper weak layers. Choose conservative terrain.
Summary
Confidence
Moderate - Uncertainty is due to the fact that persistent slabs are particularly difficult to forecast. Uncertainty is due to how quickly the snowpack will recover and gain strength.
Weather Forecast
SATURDAY NIGHT - Cloudy with flurries, 5 cm / moderate southwest wind / alpine low temperature near -12Â
SUNDAY - Mainly cloudy with scattered flurries, 5 cm / strong west wind / alpine high temperature near -5 / freezing level 1500 m
MONDAY - Mainly cloudy with scattered flurries, 5 cm / strong southwest wind / alpine high temperature near -6 / freezing level 1500 m
TUESDAY - Mainly cloudy with isolated flurries / moderate southwest wind / alpine high temperature near -7 / freezing level 1300 m
Avalanche Summary
On Friday, there were numerous reports of size 1-2 natural and human-triggered storm slab avalanches on all aspects, at all elevations.
On Thursday, there were numerous reports of size 1-2 natural, human and explosives-triggered storm slab avalanches. Many of these were triggered remotely (from a distance).Â
On Wednesday, there were a few reports of size 1.5-2 natural and human-triggered storm slab avalanches in the alpine and at treeline, on all aspects.
On Tuesday, there were several reports of natural, human and explosives-triggered avalanches up to size 3, though most were in the size 1-2 range.
During the storm last weekend and into Monday, there was a widespread natural and explosives-triggered avalanche cycle, with avalanches ranging from size 2-4. The largest avalanches were reported in the Selkirks in the northern portion of the region.
There have been a few reports from the south of the region of sporadic persistent slab avalanches failing on the late January persistent weak layer. These have been around size 2, human-triggered, and out of steep, cliffy, unsupported terrain around treeline.Â
Snowpack Summary
The region has received 60-100 cm of fresh snow in the past week. Deep wind deposits may be found in lee terrain features in the alpine and open treeline areas, and will likely remain reactive to human triggers. All of this new snow sits over weak, faceted snow from the early to mid-February cold snap.Â
There is now 70-120 cm of snow above the late January persistent weak layer which is composed of surface hoar in sheltered areas in the trees and/ or a crust on steep solar aspects. Very isolated activity on this layer has been observed recently.
Terrain and Travel
- Be carefull around freshly wind loaded features.
- Recent wind has varied in direction so watch for wind slabs on all aspects.
- If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.
- Be aware of the potential for large avalanches due to the presence of a persistent slab.
Problems
Wind Slabs
Fresh wind slabs will likely be forming as westerly winds increase in intensity throughout the day.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Persistent Slabs
40-80 cm of recent snow sits on a persistent weak layer of facets.
Another persistent weak layer buried 80-120 cm deep is composed mainly of surface hoar. We are still seeing isolated activity on this layer.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Feb 28th, 2021 4:00PM
