Avalanche Forecast
Issued: Feb 15th, 2023 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs, Deep Persistent Slabs and Persistent Slabs.
llarson,
Avalanche Canada
As a new storm travels south snow will start to accumulate throughout the day adding to the snow available for transport. Be aware of changing conditions throughout the day, and investigate the bond of old wind slabs in direct lees.
Summary
Confidence
Moderate
Avalanche Summary
Several natural very large avalanches were reported in the North of the region that failed down to the deep persistent weak layer found near the base of the snowpack.
Reports of natural and cornice-triggered wind slabs continue to trickle in, reminding us that human triggering of these layers remains possible.
Snowpack Summary
The upper snowpack consists of recent snow that has been redistributed into wind slabs directly lee of ridges at treeline and alpine elevations. Various ages of wind slabs and storm snow is generally settling and bonding.
The mid-pack is generally well consolidated with a few operations reporting continued snowpack results on a spotty surface hoar layer down roughly 80 cm. Reports of large avalanches involving various layers of surface hoar/crusts and facets within the mid-pack depth are sporadic but are a reminder of the complicated snowpack across this region.
In the lower snowpack, a layer of large and weak facets from November near the base of the snowpack remains on the radar and continues to be discussed in professional snowpack summaries.
Weather Summary
Wednesday night
Increasing cloud with isolated flurries, trace accumulations, 10 to 15 km/h southwest winds, treeline temperatures around -6 °C.
Thursday
Cloudy with flurries, 5 to 10 cm accumulation, 10 to 15 km/h southwest wind, treeline temperatures -7 °C.
Friday
Mainly cloudy, flurries 5 to 10 cm of new snow, 20 to 30 km/h winds, treeline temperatures -8 °C.
Saturday
Mainly cloudy, flurries with 5 to 10 cm accumulation, 20 to 30 km/h southwest winds, treeline temperatures -7 °C
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Avoid shallow snowpack areas, rock outcroppings and steep convex terrain where triggering is most likely.
- Be especially cautious as you transition into wind affected terrain.
- Watch for areas of hard wind slab on alpine features.
- Minimize exposure to sun-exposed slopes when the solar radiation is strong.
- Cornices become weak with daytime heating or solar exposure.
Problems
Wind Slabs
Wind slabs continue to be reactive to human triggers, this problem is found at upper elevations directly lee of ridges.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Deep Persistent Slabs
A layer of large and weak facets sits near the base of the snowpack. This layer continues on a sporadic basis to produce very large avalanches that can travel far. Riders are most likely to trigger an avalanche on this layer in steep, shallow terrain, or by triggering a smaller avalanche that could step down to this layer. Cornices will continue to grow with new snow and wind and could be the large load needed to trigger deep persistent weak layers. Your best defense is to stay diligent in choosing low-consequence terrain away from overhead exposure.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Persistent Slabs
Problematic weak layers are becoming spotty across the region, however recent large persistent slab avalanche observations continue to trickle in reminding us that these layers remain a concern in this region. Recent avalanches have been triggered by a mix of large loads like cornices.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Feb 16th, 2023 4:00PM
