Avalanche Forecast
Issued: Feb 25th, 2021 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Storm Slabs and Persistent Slabs.
kdevine,
Avalanche Canada
New snow and wind will mean that storm slabs are to be expected, and will likely be reactive to human triggering in many areas.
The potential exists to trigger deeper weak layers, resulting in large avalanches. Choose conservative terrain.
Summary
Confidence
Weather Forecast
THURSDAY NIGHT - Flurries, 10-15 cm / moderate to strong west wind / alpine low temperature near -10
FRIDAY - Mainy cloudy with flurries, 5 cm / moderate northwest wind / alpine high temperature near -10
SATURDAY - A mix of sun and cloud with a few flurries / moderate west wind / alpine high temperature near -12
SUNDAY - Mainly cloudy with scattered flurries, 5 cm / moderate to strong southwest wind / alpine high temperature near -6 / freezing level 1500 m
Avalanche Summary
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, reported in the Selkirks in the northern part of the region.
The Monashees had surprisingly limited activity up to size 2 in the same time period. Reports from Monday described size 1-2 natural, explosive, and human-triggered avalanches, as well as one report of a size 3 natural cornice triggered avalanche.
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.
Snowpack Summary
10-15 cm of new snow is expected on Thursday night with another 5 cm on Friday. This will add to the 60-100 cm of recent storm snow. 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 recent cold snap.
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, usually skier triggered in steep, cliffy, unsupported terrain around treeline in the south of the region.
Terrain and Travel
- Use conservative route selection. Choose simple, low-angle, well-supported terrain with no overhead hazard.
- Be aware of the potential for large avalanches due to the presence of a persistent slab.
- Be carefull around freshly wind loaded features.
Problems
Storm Slabs
Fresh snow combined with moderate to strong winds will likely continue to form fresh and reactive storm slabs, especially in wind-loaded areas. A change in wind direction on Friday may mean wind loading can be found on all aspects.
Cornices are experiencing rapid growth with strong west to southwest winds, use caution on ridgelines, and in terrain with cornices above.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Persistent Slabs
40-80 cm of recent snow sits overtop a thick layer of weak, sugary facets.
Another persistent weak layer buried 80-120 cm deep is composed of surface hoar. We are still seeing isolated activity on this layer.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Feb 26th, 2021 4:00PM
