Avalanche Forecast
Issued: Feb 17th, 2023 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Storm Slabs and Deep Persistent Slabs.
llarson,
Avalanche Canada
Monitor the amounts of new snow that have fallen and note whether it is consolidating into a slab. Back off into more simple terrain as the snow starts to consolidate.
Summary
Confidence
Avalanche Summary
Numerous loose dry avalanches were reported on Thursday as the storm snow started to increase in depth with little slab property.
Going forward storm slabs may become touchy, especially where the new snow overlies a recently buried surface hoar layer. Variable winds will be developing wind slabs at upper elevations directly lee of ridges and high points.
Cornices are also growing in this area and will become weak and overhanging. Small avalanches may gain enough mass to trigger deeper weak layers.
Snowpack Summary
Another 10 to 15 cm of new snow overnight brings recent snowfall totals of 30 to 40 cm of low-density snow. Storm slabs may be more reactive where they have settled on a surface hoar layer that developed earlier this week.
Moderate variable winds throughout the day will be redistributing new snow into wind slabs at treeline and alpine elevations. A melt-freeze crust can be found below 1400 m and on steep solar aspects.
The mid-pack is showing signs of strengthening. A surface hoar layer down roughly 60 to 80 cm has not produced avalanches recently but can still be found in isolated terrain features specifically sheltered, treeline, and upper below treeline.
The lower snowpack is composed of large and weak facets from November located near the base of the snowpack. Additional load or step-down avalanches over the next few days may wake this layer up.
Weather Summary
Friday night
Cloudy with snowfall overnight into Saturday morning, 10 to 15 cm accumulation, 20 to 30 km/h west winds, treeline temperatures -10 °C.
Saturday
Cloudy with snowfall briefly easing in the afternoon, 2 to 4 cm accumulation, with snowfall starting again overnight. 10 to 20 km/h west winds, treeline temperatures -10 °C.
Sunday
Cloudy with snowfall, 8 to 12 cm accumulation, 20 to 30 km/h west winds, treeline temperatures -5 °C.
Monday
Cloudy with isolated flurries, 2 to 3 cm accumulation, 5 to 10 km/h northwest winds, treeline temperatures - 10 °C.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Storm snow and wind is forming touchy slabs. Use caution in lee areas in the alpine and treeline.
- Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
- In areas where deep persistent slabs may exist, avoid shallow or variable depth snowpacks and unsupported terrain features.
- If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.
Problems
Storm Slabs
Roughly 30 to 40 cm of new snow has fallen in the region over the past few days, storm slabs will be more reactive in areas where the new snow has buried a surface hoar layer that developed earlier in the week. Expect wind slabs to be reactive at upper elevations.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Deep Persistent Slabs
A layer of large and weak facets sits near the base of the snowpack. This layer is most prominent in upper treeline and alpine elevations. Riders are most likely to trigger an avalanche on this layer in steep, shallow terrain. Your best defence is to stay diligent in choosing low-consequence terrain away from overhead exposure.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Feb 18th, 2023 4:00PM
