While wind sheltered features should offer great riding, be very cautious if you poke out into wind exposed terrain. Fresh sensitive wind slabs are expected to form as winds pick up over the next few days.
Confidence
Moderate - Wind speed and direction is uncertain
Weather Forecast
Light snowfall, cool temperatures and moderate westerly winds are expected for the first half of the workweek. There is potential for a significant warm up on Thursday. Stay tuned for details.MONDAY: Scattered cloud cover, freezing level at valley bottom, light to moderate west/southwest wind, isolated snow flurries, 1 to 5 cm possible. TUESDAY: Scattered cloud cover, freezing level at valley bottom, light to moderate west wind, 2 to 10 cm of snow possible.WEDNESDAY: Scattered cloud cover, freezing level at valley bottom, strong to extreme west winds, isolated snow flurries, 1 to 5 cm possible.Visit avalanche.ca/weather for a more detailed mountain weather forecast.
Avalanche Summary
On Saturday control work produced a few wind slabs from size 1.5 to size 2 in north facing terrain. Cornice avalanches to size 1.5 were also triggered by control work on north through northeast facing terrain. On Friday explosive control near Fernie resulted in a deep persistent avalanche; this avalanche was size 2.5 on a north aspect at 2000 metres, and is believed to have released on the mid-December facets. There was a report from last Tuesday of a natural avalanche size 3.5 on Mt Hosmer on an East aspect at 2100 metres that appears to have released on, or stepped down to the weak deep persistent layer of sugary facets near the ground. Last Wednesday we had a report of a size 3.0 avalanche on "Big Steep Mother" bowl on a northeast aspect at 2100 metres in the alpine in the Lizard range. This avalanche appears to have been started by a cornice fall that released a storm slab that then "stepped down" to deeply buried weak facets.
Snowpack Summary
20 to 40 cm of cold, light density storm snow fell Saturday night. At this time, observations show very little wind activity. However, it won't take much more than a breeze to form wind slabs in exposed terrain over the next few days. This recent storm snow rests on an older wind/storm slab formed last week that is approximately 50 to 60 cm in depth which may still be sensitive to human triggering. This older slab sits above a thick rain crust below 1900 m and a generally well settled snowpack. Isolated basal weaknesses may still exist in shallow snowpack areas. These weak areas appear to be on north-northeast aspects in the alpine.
Problems
Storm Slabs
Storm Slab avalanches are the release of a cohesive layer (a slab) of new snow that breaks within new snow or on the old snow surface. Storm-slabs typically last between a few hours and few days (following snowfall). Storm-slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.
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.