Avalanche Forecast
Issued: Mar 5th, 2022 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Persistent Slabs and Cornices.
ldreier,
Avalanche Canada
A persistent weak layer with feathery surface hoar crystals is buried 30-50 cm deep and can be found in sheltered treeline features and in the lower alpine. Warm temperatures will increase the likelihood to trigger avalanches on this layer.
Summary
Confidence
Weather Forecast
Saturday night: Clear with cloudy periods, trace of new snow, moderate northwest wind, alpine temperature 0 °C, above freezing layer between 1300 m and 2000 m.
Sunday: Mainly sunny with cloudy periods, trace of new snow, strong northwest wind, alpine high +1 °C, freezing level dropping from 2000 m to 1300 m.
Monday: Mainly cloudy with sunny periods, up to 5 cm new snow, moderate northwest wind, alpine high -5 °C, freezing level at 1000 m.
Tuesday: Mainly sunny, no precipitation, moderate to strong northeast wind, alpine high -10 °C, freezing level at 500 m.
Avalanche Summary
There have been isolated, skier reactive slab avalanches to size 1.5 on weak, feathery surface hoar crystals buried 25-50 cm at treeline and in the lower alpine.
On Friday, a natural large slab avalanche was observed on a northeast aspect that likely released on the buried surface hoar layer. Skiers triggered small (size 1) avalanches on a northeast aspect on the same layer.
A professional operation reported a slab avalanche being triggered by a wet loose avalanche from above on Thursday. And skiers triggered a size 1.5 slab avalanche from a distance away. It likely released on the buried surface hoar layer.
Snowpack Summary
There's a lot going on in the upper snowpack. Careful assessment is recommended.
There is a crust on the surface at lower elevations and on solar aspects at treeline.
Feathery, weak surface hoar crystals buried around February 26th are found down 25-50 cm, most prominently at treeline elevations. There have been reports of this layer being reactive to skier traffic.
A thick crust buried in mid-February is now found down 60-100 cm. Though there has been little avalanche activity reported on this layer, it should be treated with suspicion.
The lower snowpack is effectively bridged by the layers above, and we do not expect avalanches to be triggered in the lower snowpack at this time.
Terrain and Travel
- Carefully assess open slopes and convex rolls where buried surface hoar may be preserved.
- Surface hoar distribution is highly variable. Avoid generalizing your observations.
- Avoid travelling on slopes below cornices.
- Firm cornices can pull back into flat terrain at ridgetop if they fail.
Problems
Persistent Slabs
A layer with weak, feathery surface hoar crystals is buried 30-50 cm deep at sheltered treeline features and in the lower alpine. Isolated natural activity and skier triggered avalanches were reported on that layer in the last few days. Warm temperatures will increase the likelihood to trigger this layer.
A thick crust is buried 60-100 cm deep. There has been little avalanche activity reported on this layer, and it is uncertain if the warm weather will increase activity on this layer. Avalanches on this layer will likely reach large sizes.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Cornices
Sun and warm temperatures will likely wake up cornices. Avoid slopes with cornice hazard above.
Aspects: North, North East, East, North West.
Elevations: Alpine.
Likelihood
Expected Size
Valid until: Mar 6th, 2022 4:00PM
