Avalanche Forecast
Issued: Feb 21st, 2017 4:08PM
The alpine rating is Storm Slabs and Persistent Slabs.
, the treeline rating is , and the below treeline rating is Known problems includeSummary
Confidence
Moderate -
Weather Forecast
A mix of sun and cloud is expected on Wednesday with the possibility of lingering flurries. Alpine wind is forecast to be moderate from the west and treeline temperatures are expected to be around -10C. Similar conditions are expected for Thursday and Friday with a mix of sun and cloud, light alpine wind, and treeline temperatures remaining around -10C.
Avalanche Summary
On Monday, four natural size 1.5 storm slabs were observed in the Kootenay Pass area. These slabs were 10-20 cm thick. Ski cutting and explosives triggered numerous storm slabs size 1-1.5 throughout the region. These slabs were 10-30 cm thick and were failing on all aspects above around 1800 m elevation. On Wednesday, the recent snow is expected to remain reactive to human-triggering. Storm slabs may fail on a storm interface or could release a bit deeper on the widespread crust layer. Deeper instabilities in the snowpack also remain an isolated concern and storm slab avalanches could step down to a deeper layers resulting in very large avalanches.
Snowpack Summary
At higher elevations, 30-50 cm of recent snow typically overlies a series of crust layers from mid-February. Recent reports suggest this snow is generally well bonded to the crust. On high north aspects, a layer of surface hoar from mid-February may sit below the recent snow and may still be reactive. In exposed terrain, recent southerly winds have scoured the new snow down to the crust and formed wind slabs in leeward features. The early-February surface hoar layer is now down approximately 80-100 cm. This layer was reactive during the warm storm last week but now appears to have gone dormant. Areas with a shallow snowpack (less than around 150 cm) generally have a weak snowpack structure with a layer of sugary facets near the ground.
Problems
Storm Slabs
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Persistent Slabs
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Feb 22nd, 2017 2:00PM