Avalanche Forecast
Issued: Jan 25th, 2020 4:30PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs and Deep Persistent Slabs.
astclair,
Avalanche Canada
Areas where you can trigger an avalanche on Sunday are specific to where the wind has drifted the recent snow at higher elevations. Stay alert and monitor for these conditions if travelling in these areas.
Summary
Confidence
Moderate - Confidence is due to a stable weather pattern; little change is expected for several days.
Weather Forecast
Saturday night: Mostly cloudy, light southwest winds, alpine temperature -6 C, freezing level dropping to valley bottom.
Sunday: Mostly cloudy with isolated flurries, light southwest winds gusting moderate, alpine high temperature -3 C, freezing level around 1500 m.
Monday: Cloudy with periods of sun, isolated flurries, moderate southwest winds, alpine high temperature -2 C, freezing level around 1500 m.
Tuesday: Mix of sun and cloud, light southwest winds, alpine high temperature -2 C, freezing level around 1400 m.
Avalanche Summary
No recent avalanches have been reported. On Monday we received reports of natural and explosive triggered wind slab avalanches size 1.5-2.
On January 16th, a natural size 2 wind slab stepped down to the deep persistent basal facets below a rock band, details here.
Snowpack Summary
Recent strong westerly winds have formed stiff wind slabs in exposed areas on leeward aspects at and above treeline. A crust can be found up to treeline and on solar aspects in the alpine due to recent daytime warming and sun exposure.
A well consolidated mid-snowpack overlies a generally weak basal snowpack. The bottom 10-20 cm of the snowpack consists of facets and deteriorating crusts. Although inherently weak, the benign weather pattern this week will likely promote a decreasing trend in reactivity for this avalanche problem.
Terrain and Travel
- Watch for wind-loaded pockets especially around ridgecrest and in extreme terrain.
- Avoid steep, rocky, and wind effected areas where triggering slabs is more likely.
- If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.
Problems
Wind Slabs
Strong southwesterly winds have blown recent snow into stiff wind slabs in lee features at alpine and treeline. Natural activity may have subsided but human triggering remains possible.
Aspects: North, North East, East, South East, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Deep Persistent Slabs
We suspect that mild temperatures are gradually helping the basal weak layers to bond and the snowpack to strengthen. Deep persistent slab avalanches on these layers are unlikely but may still be triggered from shallow snowpack areas near rocky outcroppings.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Jan 26th, 2020 5:00PM
