Avalanche Forecast
Issued: Mar 5th, 2020 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs, Cornices and Deep Persistent Slabs.
JMackenzie,
Avalanche Canada
Conservative terrain selection is in order. Natural avalanches are occurring.
Summary
Confidence
Moderate -
Weather Forecast
Friday will be overcast with steady flurries and strong winds from the SW that will settle down towards the afternoon. Accumulations will be somewhere between 5 and 15cm (weather models disagree). Temperatures should be steady around the -4 mark. Saturday will be another snowy day.
Avalanche Summary
Numerous loose dry avalanches were observed in very steep Alpine terrain on N, NE and E aspects. These were generally small and did not run far down slope. A few naturally triggered slab avalanches were also observed in steep Alpine terrain on SE through N aspects. Average depths of these slides appeared to be between 40 and 60cm and were generally size 2.0 or smaller.
Snowpack Summary
A few more cm's overnight brings recent storm snow totals to 45cm. Unfortunately this storm snow has been significantly redistributed over the last several days by persistently strong to extreme SW/NW winds. Windward slopes are stripped to bare rock, and lee and cross-loaded terrain is heavily wind loaded. Expect to find wind slabs in virtually all Alpine and Treeline terrain where there is still snow on the ground. These wind slabs will be of widely variable depths and densities, and will be ripe for human triggering in much of the region. On the positive side, this season's midpack is generally strong and well consolidated. In shallow snowpack areas, the basal weaknesses remain, and will be on our radar for the remainder of the season.
Terrain and Travel
- Avoid freshly wind loaded terrain features.
- Avoid lee and cross-loaded terrain.
- Extra caution is needed around cornices under the current conditions.
- Make conservative terrain choices and avoid overhead hazard.
- Be aware of the potential for large avalanches due to the presence of a deep persistent slab.
Problems
Wind Slabs
It seems like wind slab development has been endless for the last several days. The character of these slabs (depth, density, etc.) is highly variable. Be prepared to make cautious terrain choices and avoid steep, unsupported and convex terrain.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Cornices
Cornices are large and if triggered could propagate a wind slab or a deep persistent slab on the underlying slopes.
Aspects: North, North East, East, South East, South.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Deep Persistent Slabs
Shallow snowpack areas, where trigger is more likely, are the main areas of concern with this problem. However, large triggers such as a cornice, could awaken this deep instability even in deeper snowpack regions.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Mar 6th, 2020 4:00PM
