Avalanche Forecast
Issued: Feb 9th, 2022 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Persistent Slabs and Wind Slabs.
TRettie,
Avalanche Canada
Keep an eye on daytime warming and solar input. There is some uncertainty in how the snowpack will react to the rising freezing levels. . Avoid overhead hazard.
Summary
Confidence
Weather Forecast
Wednesday night: no new snow expected. Light to moderate northwest winds. Inverted temperatures with above freezing levels treeline and above. Sub zero temperatures and valley fog down low.
Thursday: Mainly sunny with light to moderate west wind. Freezing levels reaching over 2500 m with an inversion.
Friday: sunny with freezing levels around 1500m. Light northwest winds.
Saturday: sunny with freezing levels rising to 1800m. Light northwest winds.
Avalanche Summary
On Tuesday explosives triggered persistent slab avalanches up to size 3 on northeast aspects at 2200m. These avalanches ran on the late January surface hoar and showed substantial propagation.
On Monday numerous persistent slab avalanches to size 2.5 were observed in the treeline and below. triggers included cornice falls, ski cuts and naturals. Avalanches were observed on all aspects.
On Sunday, several natural loose wet avalanches up to size 1.5 were reported. A skier triggered a size 1.5 slab on a NW aspect at 1900 m which failed down 30 cm. Just north of the region, a natural size 3.5 persistent slab was reported on a SE aspect at 2200 m which stepped down to a layer around 100 cm deep, propagated close to 1 km wide, and ran full path.
Snowpack Summary
Moist snow will likely be observed on all aspects treeline and below as well as on solar aspects in the alpine. Recent strong wind from the south have formed wind slabs in exposed terrain at higher elevations.
The January 30 interface is now typically down 20-50 cm and consists of a melt-freeze crust at lower elevations and on solar aspects extending into the alpine and surface hoar in sheltered areas at and below treeline.
The mid-January interface is now down around 40-70 cm and consists of a crust, facets, and/or surface hoar.
The early-December crust/facet persistent weak layer is buried down 100-200 cm. It had been responsible for significant avalanche activity in this region during the first half of January but is now considered dormant. See this forecaster blog on how to manage this layer as it may come into play again later this season.
Terrain and Travel
- Be aware of the potential for large avalanches due to the presence of buried weak layers.
- Look for signs of instability: whumphing, hollow sounds, shooting cracks, and recent avalanches.
- Back off slopes as the surface becomes moist or wet with rising temperatures.
- Be careful as you transition into wind affected terrain.
Problems
Persistent Slabs
20-50 cm of settling snow sits over the January 30 surface hoar. This layer was responsible for numerous natural and human-triggered avalanches over the past week. Treat open slopes at and below treeline with extra caution where the surface hoar is most prominent.
The weak layer from mid-January down 40-70 cm remains a concern in isolated areas and avalanches may still have the potential to step-down.
The likelihood of triggering these layers could increase as the freezing levels rise.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Wind Slabs
Recent strong winds from the south have formed wind slabs in exposed terrain at higher elevations. These slabs are particularly reactive where they overlie buried surface hoar.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Feb 10th, 2022 4:00PM
