Avalanche Forecast
Issued: Feb 3rd, 2017 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Persistent Slabs.
tim haggarty,
Avalanche Canada
There is a lot of uncertainty with the weather, including snowfall amounts, over the weekend. If significant snowfall arrives expect to see an increase in avalanche activity on the persistent layers.
Summary
Weather Forecast
A low over the coast is spreading a stream of moisture to the Southern Rockies while competing polar air overlies our forecast area. The amount of snow that arrives depends on which of these two air masses is the strongest and where the boundary between them ends up varying between 10 and 30cm. Temps and winds will be equally difficult to predict.
Snowpack Summary
Strong winds last weekend created extensive wind effect TL and above. A generally weak snowpack exists below 2000m. At 2000m there is about 140 cm with the Jan 17 surface hoar layer down 30cm. In the mid-pack, the Dec facets are around 20cm thick. Weak facets can also be found at the base of the snowpack associated with an ice crust.
Avalanche Summary
There was a small avalanche cycle last weekend from strong winds. The activity has slowed significantly due to decreased winds and cooling temperatures. No avalanches reported Thursday or Friday.
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. Slab development will make triggering these layers more likely this weekend.
- Use conservative route selection, choose moderate angled and supported terrain with low consequence.
- Dig down to find and test weak layers before committing to a line.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Feb 4th, 2017 4:00PM
