Avalanche Forecast
Issued: Jan 28th, 2022 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs and Persistent Slabs.
TRettie,
Avalanche Canada
Keep an eye on the wind. Thin but touchy wind slabs are likely to form throughout the day. Sensitivity to triggering these slabs will be greatest where they have formed over surface hoar.
Summary
Confidence
Weather Forecast
Friday night: Stormy weather with up to 5cm of snow throughout the day. Moderate to strong south winds and a low of -6 at 1600m.
SATURDAY: Stormy weather continues with another 5-10cm of snow and moderate to strong wind from the southwest. Freezing level rising to 1000m.
Sunday: some light flurries with light west winds. High of -4 at 1600m.
Monday: some light flurries with moderate west winds. High of -4 at 1600m.
Avalanche Summary
two natural cornice triggered avalanches up to size 3 were observed over the past few days on southeast aspects at treeline.
Earlier in the week there were several large machine triggered avalanches on persistent weak layers throughout the region.
Snowpack Summary
As the storm builds on Friday and Saturday new wind slab will form over a variety of surfaces including facets, surface hoar and old wind slab. The new snow will not bond well to these surfaces. In the southern part of the region it is possible to find a rain crust up to 1500m.
Below this we have two persistent weak layers, the first is a surface hoar layer from mid January buried down approximately 30cm. The second is a layer of facets from early January which is now down 50 to 80cm, it has been most reactive where wind slab has formed above it and will now likely require a large load to trigger.
Terrain and Travel
- Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
- Be aware of the potential for large avalanches due to the presence of buried persistent weak layers.
- Wind slabs are most reactive during their formation.
Problems
Wind Slabs
New touchy wind slabs will likely form throughout the day on Friday and Saturday. Sensitivity to triggering will be greatest where wind slab has formed over surface hoar. Strong winds could mean that wind slab could form further down slope than expected.
Aspects: North, North East, East, South East, West, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Persistent Slabs
The mid January surface hoar layer is a developing problem that could start to produce more avalanches in the near future. Use extra caution in sheltered terrain at treeline where preserved surface hoar is more likely to exist.
The early January facet layer is now down as deep as 80cm and might require a large load such as a cornice fall or a smaller avalanche in the layers above in order to be triggered. This problem is likely most concerning on high north and east facing terrain.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Jan 29th, 2022 4:00PM
