Avalanche Forecast
Issued: Feb 27th, 2023 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs and Deep Persistent Slabs.
JA,
Avalanche Canada
Wind transport continues to build wind slab at tree line and in the alpine. Minimize your overhead hazard and avoid wind-loaded terrain. If triggered, wind slabs may step down to the deep persistent problem resulting in large avalanches.
Summary
Confidence
Moderate
Avalanche Summary
Size 2 and 2.5 deep persistent slab observed S end of Medicine lake - one starting low in north facing alpine start zone with a 1m deep crown.
Last week we experienced a widespread avalanche cycle on all aspects in the alpine. Many of these avalanches started as wind slabs and stepped down to the deep persistent facet layer. Most were size 2-3 but one size 4 was observed. Most notably the main Buck Lake slide path and the Churchill South slide path ran into the ski lines. Â
Don't forget to post avalanche observations to the MIN.
Snowpack Summary
Recent strong winds from the north and southwest have redistributed surface snow increasing the wind slab hazard at and above treeline. Ridgetop has been scoured in most locations with wind effect visible throughout the alpine.
The upper snowpack consists of 20-50 cm of settled snow or wind slab sitting on top of a generally weak mid and lower snowpack. Facets and depth hoar linger at the base of the snowpack with the height of snow varying from 60 to 160cm.
Weather Summary
Tuesday
Cloudy with sunny periods and isolated flurries.
Precipitation: Trace.
Alpine temperature: High -10 °C.
Ridge wind east: 10 km/h.
Freezing level at valley bottom.
Wednesday
Cloudy with sunny periods and isolated flurries.
Precipitation: Trace.
Alpine temperature: Low -20 °C, High -11 °C.
Ridge wind west: 15 km/h gusting to 45 km/h.
Freezing level at valley bottom.
Thursday
Cloudy with sunny periods and isolated flurries.
Precipitation: Trace.
Alpine temperature: Low -20 °C, High -12 °C.
Ridge wind southwest: 20-40 km/h.
Freezing level at valley bottom.
Detailed weather forecasts from Avalanche Canada: https://www.avalanche.ca/weather/forecast
Terrain and Travel Advice
- Expect slab conditions to change drastically as you move into wind exposed terrain.
- If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.
Problems
Wind Slabs
Recent strong to extreme winds from the SW with some new snow continue to build wind slabs in open areas. Be aware that last weeks north wind may have created some lingering wind slabs in abnormal locations due to reverse loading.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Deep Persistent Slabs
The bottom of the snow pack is inherently weak with well developed Facets and Depth Hoar. Natural avalanches continue to step down to this layer resulting in large avalanches.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Feb 28th, 2023 4:00PM
