Confidence
Fair - Forecast snowfall amounts are uncertain on Monday
Weather Forecast
Monday: Moderate snowfall / Moderate to strong southerly winds / Freezing level at 1300mTuesday: Moderate snowfall / Moderate to strong southwest winds with extreme gusts / Freezing level at 1300mWednesday: Mix of sun and cloud with a possibility of flurries / Light ridgetop winds / Freezing level at 900m
Avalanche Summary
On Friday a skier remotely triggered a size 2 slab avalanche on a northwest facing alpine slope just north of the region. On Saturday, 2 size 2 skier-triggered avalanches (1 was remotely triggered from 25m) occurred in the Monashees. The February 10th interface is thought to be the culprit in these events. A few remotely triggered size 1 hard wind slabs were also noted on Saturday in exposed lee terrain. They formed in response to strong winds and redistribution of surface snow on Friday night.
Snowpack Summary
A developing storm slab overlies surface hoar in sheltered areas, a sun crust on solar aspects and touchy thin wind slabs in exposed terrain. The big news remains a mix of weak surfaces which were buried on February 10th. This persistent interface lies between 70 and 120cm below the surface, and includes surface hoar, well developed facets and a mix of hard surfaces which remain widespread at all aspects and elevations. Although avalanche activity has generally tapered-off at this interface, large destructive avalanches are still a very real concern with ongoing reports of remote-triggering, "whumpfing" and sudden snowpack test results. For the most part, the mid and lower snowpack are strong and well consolidated.
Problems
Persistent Slabs
Persistent Slab avalanches are the release of a cohesive layer of snow (a slab) in the middle to upper snowpack, when the bond to an underlying persistent weak layer breaks. Persistent layers include: surface hoar, depth hoar, near-surface facets, or faceted snow. Persistent weak layers can continue to produce avalanches for days, weeks or even months, making them especially dangerous and tricky. As additional snow and wind events build a thicker slab on top of the persistent weak layer, this avalanche problem may develop into a Deep Persistent Slab.
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.