Regions
Northwest Coastal.
Some thin new wind slabs are expected to develop with the forecast new snow. New snow is not expected to bond well to the old hard surface where surface hoar and/or facets exist.
Confidence
Fair - Timing, track, or intensity of incoming weather system is uncertain
Weather Forecast
Overnight and Wednesday: Overcast with moderate Westerly winds overnight and 3-5 cm of snow above about 700 metres. The freezing level is expected to continue to drop during the day as light flurries continue.Thursday: A few more cm of snow are forecast for the morning before the winds shift to the Northeast and colder arctic air enters the region.Friday: Mostly clear with moderate Northerly winds and freezing levels at valley bottoms. Alpine temperatures around -15.
Avalanche Summary
No new avalanches reported.
Snowpack Summary
Below freezing temperatures have developed a solid melt-freeze crust at all elevations and on most aspects. Some dry facetted snow may exist on sheltered North aspects. New surface hoar has been reported on slopes that are sheltered from the sun at and below treeline. A well settled mid and lower snowpack may rest on basal facets, especially in thin snowpack areas at higher elevations.
Problems
Deep Persistent Slabs
Deep Persistent Slab avalanches are the release of a thick cohesive layer of hard snow (a slab), when the bond breaks between the slab and an underlying persistent weak layer deep in the snowpack. The most common persistent weak layers involved in deep, persistent slabs are depth hoar or facets surrounding a deeply buried crust. Deep Persistent Slabs are typically hard to trigger, are very destructive and dangerous due to the large mass of snow involved, and can persist for months once developed. They are often triggered from areas where the snow is shallow and weak, and are particularly difficult to forecast for and manage.