Avalanche Forecast
Issued: Jan 28th, 2017 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Persistent Slabs and Wind Slabs.
stephen holeczi,
Avalanche Canada
With elevated winds, we are seeing isolated natural avalanches that are hard to predict. Be suspect of slopes where a slab sits over the weaker layers below, and watch how any winds are loading alpine features. SH
Summary
Weather Forecast
Alpine temperatures in the -5 to -9 range for Sunday and strong West winds (up to 100kmh). 5 cm is currently forecast for Sunday evening. Cooler temperatures for Monday.
Snowpack Summary
In many areas, a generally weak snowpack exists until 2000-2200m . At 2000m, there is generally 135cm of snow, with the Jan 17 surface hoar layer down 25cm producing sudden planar test results - but minimal slab formation above. In the mid-pack, the Dec facets are 20cm thick, and near the ground some weak facets sit just below on old ice crust.
Avalanche Summary
A 300m fracture line was seen yesterday on Cathedral Peak which was 50cm deep on a N-NE aspect at treeline/low alpine. Wind loading from yesterday was the suspected culprit. East of the divide new reactive wind slabs were reported in the alpine, and this is likely in Little Yoho as well.
Confidence
Problems
Persistent Slabs
The generally weak, facetted mid pack is producing moderate to hard shears. In the upper snowpack around treeline a buried layer of surface hoar produces variable shears. Pay close attention to the slab properties overlying these layers.
- Use conservative route selection, choose moderate angled and supported terrain with low consequence.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Wind Slabs
New slabs will be reactive in the short term while wind speeds remain elevated. Watch locally for their formation in exposed lee and cross-loaded areas.
- Use caution in lee areas. Recent wind loading have created wind slabs.
Aspects: North, North East, East, South East.
Elevations: Alpine.
Likelihood
Expected Size
Valid until: Jan 29th, 2017 4:00PM
