Avalanche Forecast
Issued: Dec 25th, 2021 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs, Loose Dry and Deep Persistent Slabs.
Garth Lemke,
Happy Holidays to everyone from Jasper Visitor Safety!Should you brave the cold, be vigilant for new wind slabs.
Summary
Weather Forecast
Sunday will be sun with mixed clouds and flurries, a trace of new snow, -28C, and light East winds. Monday will be similar with slightly warmer temperatures. Tuesday may have more sun but remain frigid.
Snowpack Summary
35cm of snow arrived Dec 22-23 with moderate to strong SW winds. Wind slab developed in the alpine and on exposed terrain features at treeline. The mid-pack is generally supportive with an exception of a weak rain crust 30-40 cm down found up to 1950m. Cold temperatures will accelerate faceting.
Avalanche Summary
Friday's avalanche control produced numerous 30cm thick wind slabs up to size 2 on wind loaded open tree line features. One result buried the road 2m deep for a 100m. Surprisingly, explosive triggers did not trigger the deeper instabilities. Numerous dry loose resulted from explosives and natural activity also occurred up to size 1.5.
Confidence
Due to the number and quality of field observations on Sunday
Problems
Wind Slabs
Up to 35cm of new snow Dec 22-23rd with moderate to strong winds created wind slabs on lee and cross loaded features. Slab development can be found low in terrain features. A rain crust 30cm down is a suspect weak layer in BTL wind affected snow.
- Use caution in lee and cross-loaded terrain near ridge crests.
- Watch for stiffer feeling snow. Avoid areas that appear wind loaded.
Aspects: North, North East, East, South East, South, North West.
Elevations: All elevations.
Likelihood
Expected Size
Loose Dry
A Dry loose problem will persist for the short term particulary from steep terrain.
- Avoid travelling on ledges and cliffs where sluffing may have severe consequences.
- Be careful of loose dry power sluffing in steep, confined or exposed terrain.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Deep Persistent Slabs
This problem, although stubborn, persists in isolated alpine terrain and can initiate with a large trigger or rapid loading. Use extra caution in thin areas were humans are most likely to trigger this high consequence layer.
- Use caution in thin snowpack areas.
Aspects: All aspects.
Elevations: Alpine.
Likelihood
Expected Size
Valid until: Dec 26th, 2021 4:00PM
