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.
cgarritty,
Avalanche Canada
Lots of regional variability for Sunday. Elevations that saw only rain on Saturday will trend toward LOW danger with an overnight refreeze. Increased danger will exist in areas where new snow accumulated - especially where it has been redistributed by wind.
Summary
Confidence
Moderate - Uncertainty is due to the limited number of field observations.
Weather Forecast
Saturday night: Becoming clear with isolated flurries easing into the morning. Strong west winds becoming light by morning.
Sunday: Sunny. Calm or light west winds. Alpine high temperatures around -12.
Monday: Mainly sunny. Calm or light northwest winds. Alpine high temperatures around -13.
Tuesday: A mix of sun and cloud with cloud increasing over the day. Light to moderate southwest winds increasing over the day. Alpine high temperatures around -13.
Avalanche Summary
Reports from Friday showed small (size 1) wind slabs able to be triggered with ski cutting in the Castle area. More intense snowfall and wind throughout Saturday are likely to have spurred a natural avalanche cycle, focused in high elevation, wind-exposed areas.
On Thursday a cornice fall released a size 2 slab avalanche on the slope below on an east aspect at 2150 m.Â
On January 16th, a natural, size 2 wind slab stepped down to the deep persistent basal facets below a rock band, details here.
While natural avalanche activity is likely to taper off now that the storm has ended, human-triggering will remain possible at higher elevations where new snow exists and has been exposed to strong or extreme winds.
Snowpack Summary
New snow combined with strong southwesterly winds will continue to build slabs in exposed areas. Cornices have been noted in many areas. A crust can be found up to around 1700 m due to previous warming and sun exposure.Â
A well consolidated mid-pack overlies a generally weak basal snowpack. The bottom 10-20 cm of the snowpack consists of facets and deteriorating crusts. While there has been little in the way of avalanche activity on this layer recently, there is potential for it to show up an avalanche reports from the warm wet storm over the weekend. Areas that are most likely to harbor this problem are shallow, rocky start zones.Â
Terrain and Travel
- Be alert to conditions that change with elevation, aspect and exposure to wind.
- If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.
- When a thick, melt-freeze surface crust is present, avalanche activity is unlikely.
Problems
Wind Slabs
Our new snow at higher elevations has seen extensive wind redistribution as a result of strong to extreme southwest winds. Expect to find increasingly deep and reactive new wind slabs as you gain elevation on Sunday. More widespread (all aspects) storm slabs may be found in eastern parts of the region that saw snowfall continue as temperatures dropped on Saturday.
Aspects: North, North East, East, South East, South, North West.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Feb 2nd, 2020 5:00PM
