Avalanche Forecast
Issued: Mar 5th, 2018 5:16PM
The alpine rating is Persistent Slabs and Cornices.
, the treeline rating is , and the below treeline rating is Known problems includeSummary
Confidence
Moderate -
Weather Forecast
TUESDAY: Clouds clearing in the morning and then sunny in the afternoon, light west wind, freezing level rising to around 1000 m.WEDNESDAY: Sunny, light wind, freezing level rising to around 1300 m.THURSDAY: Flurries increasing throughout the day with 5-10 cm of snow by the afternoon, moderate southwest wind, freezing level rising to around 1200 m.
Avalanche Summary
On Sunday, a MCR report from the Blackcomb backcountry has a picture of a large remotely triggered avalanche (see here). This size 3 avalanche occurred on a west aspect around 1900 m and presumably failed on the buried surface hoar layer. A few similar, but slightly smaller, avalanches were reported in nearby terrain at similar elevations and on a range of aspects. This persistent weak layer will likely remain reactive to human triggers throughout the week.On Saturday, a few natural size 1-2 slabs were reported on north aspects and numerous wet loose avalanches were reported on steep south-facing terrain. Several small snowmobile triggered avalanches (size 1) were reported at treeline elevations in the Brandywine area.On Friday, a few human triggered avalanches up to size 2.5 were reported. A size 1.5 and a size 2.5 were triggered on southwest facing slopes between 1900 and 2000 m. These likely failed on the buried persistent weak layers.
Snowpack Summary
A thin sun crust has formed on solar aspects and the surface is wind affected in most exposed terrain. Last week's storms buried a weak layer composed of soft facets, surface hoar, and/or crust roughly 50-100 cm below the surface. This layer has produced whumpfing, sudden results in snowpack tests, and some remotely triggered avalanches. Lots of the activity has been on buried surface hoar on north aspects at upper treeline elevations. The snowpack is well settled and strong beneath this interface. Variable winds in the past month have produced cornices on many ridgelines. They will become touchier as they grow in size, as temperatures rise, and when they are subject to the strong late-winter sun on clear days.
Problems
Persistent Slabs
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Cornices
Aspects: North, North East, East, South East, South, South West.
Elevations: Alpine.
Likelihood
Expected Size
Valid until: Mar 6th, 2018 2:00PM