Avalanche Forecast
Issued: Feb 4th, 2022 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Persistent Slabs and Storm Slabs.
mconlan,
Avalanche Canada
Human triggering of large avalanches will remain very likely on Saturday, particularly where recent snow is loading a buried weak layer.
Summary
Confidence
Weather Forecast
FRIDAY NIGHT: Cloudy with snowfall, accumulation 5 to 15 cm, 40 to 60 km/h southwest wind, alpine temperature -7 C.
SATURDAY: Cloudy with snowfall, accumulation 2 to 5 cm, 30 to 50 km/h west wind, alpine temperature -7 C, freezing level 1100 m.
SUNDAY: Mix of sun and cloud with no precipitation, 30 km/h southwest wind, alpine temperature -3 C, freezing level rising to 1700 m.
MONDAY: Cloudy with snowfall, accumulation 5 to 10 cm, 40 km/h southwest wind, alpine temperature -5 C, freezing level 1400 m.
Avalanche Summary
We haven't received reports from Friday but suspect that both natural and rider-triggered avalanches occurred during the stormy weather. Large avalanches are expected in areas where the buried surface hoar described in the Snowpack Summary exists.
Looking towards Saturday, Avoidance of avalanche terrain is your best bet for having a safe day. Storm and wind slabs will be very touchy due to all the recent snow and wind. Rain at low elevations will also quickly destabilize the storm snow. The snow will need time to stabilize.
Snowpack Summary
Storm totals are expected to reach around 30 to 50 cm by the end of Saturday. The snow has likely formed storm slabs in sheltered areas and wind slabs in lee terrain features from strong southwest wind. These slabs will remain touchy for the remainder of the weekend as the freezing level rises and the air gets warmer.
The snow will be particularly touchy where it is loading a weak layer of surface hoar crystals. This layer is likely anywhere from 50 to 100 cm deep. Reports suggest that the surface hoar is most prominent in sheltered openings at and below treeline but could extend into wind-sheltered terrain in the alpine. Example terrain features to treat as suspect include the lee side of protected ridges, openings in the trees, cut blocks, and burns. On south aspects, a melt-freeze crust may exist instead of surface hoar.
The lower snowpack is generally strong and well-bonded.
Terrain and Travel
- Travel in alpine terrain is not recommended.
- Avoid all avalanche terrain during periods of heavy loading from new snow and wind.
- Potential for wide propagation exists, fresh slabs may rest on surface hoar, facets and/or crust.
- Watch for signs of instability like whumpfing, hollow sounds, shooting cracks or recent avalanches.
Problems
Persistent Slabs
New snow is loading a widespread weak layer of surface hoar crystals. The layer may be found around 50 to 100 cm deep and is most prominent in areas sheltered from the wind at and below treeline. Example terrain features to particularly treat as suspect include the lee side of ridges, openings in trees, cut blocks, and burns.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Storm Slabs
Snow will continue to accumulate into Saturday morning, which has formed new slabs. Expect to find storm slabs in sheltered areas and wind slabs in wind-exposed terrain from strong southwest wind.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Feb 5th, 2022 4:00PM
