Avalanche Forecast
Issued: Mar 8th, 2020 8:00AM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Persistent Slabs and Wind Slabs.
Kate Ryan,
Parks Canada
Happy Daylight Savings!
Give your minds extra time to assess slopes for the Feb 22nd weak layer.
We are moving into a lower probability/ high consequence hazard window.
Summary
Weather Forecast
A brief ridge of high pressure sets up today before a stronger frontal system arrives tuesday.
Today: mix of sun and cloud and no precip. Winds light from the west. Alpine high -11C
Tonight: cloudy with clear periods and no precip. Light west winds. Alpine low -13C
Tomorrow: mix of sun and cloud, no precip. Moderate SW winds. Alpine high -11C
Snowpack Summary
25cm+/- of storm snow has been redistributed by moderate S'ly winds near ridgecrests in the alpine and exposed treeline. Below these slabs, the Feb 22nd persistent weak layer is now buried down 50-80cm, and consists of 3-7mm surface hoar on all aspects up to 2450m, and a crust on solar aspects. In some locations, this surface hoar sits on a crust.
Avalanche Summary
Two large (2-2.5) avalanches occurred in the East highway corridor yesterday.
On Friday, Glacier National Park VS staff responded to a InReach call for a snowmobile triggered size 2.5 slide that occurred inside the E boundary of Glacier National Park in the Bald Hills. Evidence indicated 2 sleds were involved and the group self extricated.
Confidence
Problems
Persistent Slabs
The Feb 22 Surface Hoar/ sun crust layer is down ~100cm at TL in the W end of the park & 50-80cm in the east. It's a likely depth for skier triggering in shallower snowpack areas. This problem is decreasing in probability but remains high consequence
- Avoid steep convexities or areas with a thin or variable snowpack.
- Be aware of the potential for wide propagations.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Wind Slabs
Moderate to strong southerly winds this week have formed wind slabs in the alpine and exposed areas at treeline. If triggered, these wind slabs have the potential to step down to the Feb 22nd SH/ sun crust layer.
- If triggered the windslabs may step down to the Feb 22 SH layer with potential for large avalanches.
- Use caution in lee and cross-loaded terrain near ridge crests.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Mar 9th, 2020 8:00AM
