Avalanche Forecast
Issued: Feb 1st, 2020 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs and Persistent Slabs.
cgarritty,
Avalanche Canada
Ease into terrain cautiously on Sunday and be prepared to step back if you encounter signs of instability. Seek sheltered, low density snow and keep clear of overhead hazards - especially if they're in the sun.
Summary
Confidence
Moderate - Uncertainty is due to the limited number of field observations.
Weather Forecast
Saturday night: Cloudy with isolated flurries and a trace of new snow. Moderate southwest winds, easing into the morning.
Sunday: A mix of sun and cloud, clearing over the day. Light to moderate northwest winds. Alpine high temperatures around -15.
Monday: Clear in the morning, becoming cloudy over the day with light flurries overnight. Light southwest winds, increasing over the day and becoming strong overnight. Alpine high temperatures around -10.
Tuesday: Cloudy with isolated flurries and a trace of new snow, increasing overnight. Moderate to strong southwest winds, easing over the day before increasing again overnight. Alpine high temperatures around -3.
Avalanche Summary
Poor visibility has limited avalanche observations over recent days, however reports from Friday suggest a natural avalanche cycle was ongoing in areas like the Howsons where up to 100 cm of recent storm snow exists. Aerial observations between the Howsons and Smithers on Friday revealed significant natural activity in avalanche tracks and runouts in spite of limited visibility.
Snowpack Summary
Widespread wind and storm slabs now exist in areas where up to 50 to 70 cm storm snow accumulated with strong winds. Below the new snow is a weak layer of facets that developed in the mid-January arctic outflow event. At treeline, a suspect layer of surface hoar may be found 1 m below the surface. Below treeline the new snow rests on a melt-freeze crust and a well settled snowpack.
A deep crust/facet layer lurks at the base of the snowpack, especially in shallower (eastern) areas that was reactive earlier in January. While it is promising that last week's snowfall did not trigger avalanches on this deep persistent weak layer, there is a lingering uncertainty whether avalanches in surface layers may step down to it. Triggering this layer is most likely in shallow, rocky start zones or with a large load such as cornice failure or avalanche.
Terrain and Travel
- Storm snow and wind is forming touchy slabs. Use caution in lee areas in the alpine and treeline.
- Expect slab conditions to change drastically as you move into wind exposed terrain.
- Watch for signs of instability like whumpfing, hollow sounds, shooting cracks or recent avalanches.
- Storm slabs in motion may step down to deeper layers resulting in large avalanches.
Problems
Wind Slabs
Strong to extreme winds have been redistributing new snow in the region into fresh wind slabs. Expect this problem to be greatest at higher elevations and in western parts of the region that received greater recent snow amounts. Keep your guard up around steep slopes in sheltered areas where a stubborn storm slab may still react to a human trigger.
Aspects: North, North East, East, South East, South.
Elevations: All elevations.
Likelihood
Expected Size
Persistent Slabs
A layer of weak, faceted snow from the January cold snap is now buried about 50-80 cm deep. Avalanches in surface snow layers currently carry a risk of stepping down to this weak layer to create a larger, more destructive avalanche.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Feb 2nd, 2020 5:00PM
