Avalanche Forecast
Regions: Brazeau, Churchill, Cirrus-Wilson, Fryatt, Icefields, Jasper, Maligne, Marmot, Miette Lake, Pyramid.
Deep persistent slab avalanches have been reported in the region. Although triggered by explosives, this is a warning sign that this layer is reaching its threshold. As we enter a period of warming temperatures, be extra vigilant in your terrain choices.Keep in mind your overhead hazard during the warmest part of the day.
Confidence
Moderate
Avalanche Summary
Marmot Basin has reported a few explosive triggered large deep persistent slabs in the alpine on north aspect. Parkway patrol did not observe any new natural avalanche activity on Thursday. A few small loose wet slides have been observed along the Maligne Road on solar aspects, in steep rocky terrain below the tree line.
Snowpack Summary
The snowpack continues to be weak and largely unsupportive, though recent storm snow has improved travel. HS at tree-line is 45-75cm. Ski penetration is down ~30cm which shows that there is some structure (slab) in the mid-pack. An interface down ~25cm shows up in snowpack tests; while in the field, reactivity will be subject to the strength of the slab over the PWL layer. Expect temperature crusts at lower elevations as freezing levels rise above valley bottom.
Weather Summary
Friday
Cloudy with sunny periods. Precipitation: Nil. Alpine temperature: High -5 °C. Mostly light ridge wind occasionally gusting to 35 km/h. Freezing level: 1500 metres.
The Mountain Weather Forecast is available at Avalanche Canada https://avalanche.ca/weather/forecast
Terrain and Travel Advice
- Back off if you encounter whumpfing, hollow sounds, or shooting cracks.
- A moist or wet snow surface, pinwheeling and natural avalanches are all indicators of a weakening snowpack.
Avalanche Problems
Persistent Slabs
Recent reported avalanches in the Icefields were down ~30cm on this suspect interface. This layer is concerning when there is a cohesive slab overlying it. Watch for the warnings in the snowpack like shooting cracks.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood: Possible
Expected Size: 1 - 2
Deep Persistent Slabs
Triggering may be possible in isolated features. Approaches or transitions with steep rocky terrain are particularly worrisome. Watch for signs of whumping and cracking.
Aspects: All aspects.
Elevations: Alpine.
Likelihood: Possible
Expected Size: 1 - 3
Loose Wet
This problem is isolated to where there is enough snow to avalanche below tree-line with the high freezing levels. Especially concerning for ice climbers are low-elevation south aspect gullies, which act as heat traps and can produce small sluffs with significant consequences.
Aspects: All aspects.
Elevations: Below Treeline.
Likelihood: Possible
Expected Size: 1 - 1.5