Avalanche Forecast
Issued: Dec 16th, 2019 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Storm Slabs and Persistent Slabs.
MBender,
Avalanche Canada
Snowfall combined with moderate to strong southwest wind Monday night through Tuesday will increase avalanche danger to HIGH.
Summary
Confidence
Moderate - Uncertainty is due to the timing, track, & intensity of the incoming weather system.
Weather Forecast
MONDAY NIGHT: Snow, accumulation 10-15 cm, moderate to strong southwest wind, alpine high temperature -9 C.
TUESDAY: Flurries, accumulation 10-15 cm, moderate to strong southwest wind, alpine high temperature -4 C.
WEDNESDAY: Flurries, accumulation 5-10 cm, moderate south wind, alpine high temperature -6 C.
THURSDAY: Scattered flurries, moderate southwest winds, alpine high temperature -7 C.
Avalanche Summary
On Saturday there were 3 reports of skier triggered persistent and storm slab avalanches running on surface hoar buried 25-50 cm deep. These ranged from size 1 to 2 and were on north, west and south aspects between 1400 and 2000m. Two of these were remotely triggered (from a distance). There was also a report of a snowmobile triggered size 2 persistent slab avalanche on an east aspect at 2300m
Expect to see an increase in natural avalanche activity as storm snow accumulates through Monday night and Tuesday.
Snowpack Summary
25-40 cm of recent snow has accumulated above a widespread layer of large, feathery surface hoar crystals. New snow is expected to continue to accumulate above this layer over the next few days, making it more sensitive to human-triggering.
A weak layer formed in late November is now buried around 1 m plus below the surface. This is the layer of concern relating to the persistent slab avalanche problem. The weak layer may present as surface hoar, a crust, facets or a combination, depending on elevation and aspect. Below this, a variety of crusts from late October are buried deeper in the snowpack.
Problems
Storm Slabs
Snow accumulating above a buried layer of weak surface hoar will create a touchy storm slab problem. The conditions are primed for human triggered avalanches.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Persistent Slabs
A couple of weak layers formed in late November and early December are now sitting about 1 m below the surface. This layer may present as surface hoar, a crust, facets or a combination of those, depending on elevation and aspect.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Dec 17th, 2019 5:00PM
