Avalanche Forecast
Issued: Feb 10th, 2020 2:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Storm Slabs and Cornices.
jfloyer,
Avalanche Canada
Danger will rise rapidly during storms expected on Tuesday and Thursday because of a buried surface hoar layer.
Summary
Confidence
Moderate - Uncertainty is due to the track & intensity of the incoming weather system.
Weather Forecast
Monday night: 15-25 cm new snow with strong westerly winds. Treeline temperatures around -6C.
Tuesday: 10-15 cm new snow with strong northwesterly winds. Treeline temperatures around -6C.
Wednesday: Mostly dry with a mix of sun and cloud. Treeline temperatures around --10C.
Thursday: 10-20 cm new snow with strong southwesterly winds. Treeline temperatures around -6C.
Avalanche Summary
There were no slab avalanches reported in this region between Feb 6 and Feb 10.
I expect storm slab avalanches will rapidly develop on Tuesday and remain sensitive to human triggering through this week.
We are aware of an avalanche that occurred Sunday Feb 2 in the Upper Burnt area that is presumed to involve a snowmobiler. Preliminary information indicates that avalanche was a size 2.5 on a southeast aspect at 1600 m with a fracture line depth of 130 cm.
Snowpack Summary
A layer of surface hoar has become buried by light snow. Until it is buried approximately 30 cm or so it poses little hazard in sheltered areas. However, in the lee of ridge lines, where fresh wind slabs are likely to have formed, it may make avalanches easier to trigger.
Approximately 40-60 cm recent storm snow sits above a thin rain crust from the warm, wet storm on Feb 01. This rain crust has been reported to exist up to treeline elevations around 1700 m. Initially this layer was described as reactive and was the focus of a number of avalanches. However, it now appears to be gaining strength and probably won't end up being a significant long-term weak layer.
In the mid-pack there may still be a layer of surface hoar buried in late December. It's gaining strength, but should remain a concern since snowpack tests still demonstrate this layer has the potential to slide, albeit in isolated areas and/or with very large triggers.
Terrain and Travel
- Avoid freshly wind loaded features, especially near ridge crests, roll-overs and in steep terrain.
- Back off if you encounter whumpfing, hollow sounds, or shooting cracks.
- Cornice failure may trigger large avalanches.
Problems
Storm Slabs
Expect avalanches to become easily triggered as storm snow amounts increase, particularly in wind-affected areas.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Cornices
Cornices have been reported to be especially large. Cornice collapses become likely in warmer temperatures and/or when the sun is out. The weight of a large cornice dropping could be sufficient to trigger a large avalanche on the slope below.
Aspects: North, North East, East.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Feb 12th, 2020 5:00PM
