Regions
Northwest Coastal.
Widespread wind effect has been reported from the alpine. The best and safest riding can probably be found on sheltered slopes at treeline and below.
Confidence
Moderate - Intensity of incoming weather systems is uncertain on Thursday
Weather Forecast
WEDNESDAY: partly cloudy with flurries possible in the afternoon, light to moderate southerly winds, freezing level rising to 1000m through the day. THURSDAY: snow overnight and through the day (up to 10cm around Terrace and 5cm further inland), moderate to strong southerly winds, 1500m freezing level. FRIDAY: snow continues (another 15-20 for Terrace, 10 inland), moderate to strong southerly winds, 1500m freezing level.
Avalanche Summary
A couple of natural and skier triggered storm and wind slab avalanches with limited propagation were reported over the last couple of days. Cornices are large and fragile. Northeast of Bell 2 a natural avalanche at treeline was observed to have stepped down to the early January surfaces hoar on Sunday. While this avalanche technically occurred in the Northwest Inland region it is a good reminder that this layer remains a concern, especially in the thinner snowpack areas.
Snowpack Summary
The upper snowpack continues to settle and gain strength although some lingering mid-storm instabilities are still showing up in snow profiles. A thin crust may cap moist snow at lower elevations and on slopes that see direct sun. Recent winds have formed wind pressed surfaces in exposed terrain and loaded lee features. 40-100cm of snow now sits above a melt freeze crust buried on February 12th. This crust extends up to about 2000m. Although the snow above is bonding well to this crust in most places, recent snow pit tests northwest of Terrace produced failures on or in facets just below this layer under moderate to hard loads. Below this, a layer of surface hoar buried late in January remains a concern in thinner snowpack areas in the east and north of the region. The snowpack in these areas may also sit on a weak base of facets near the ground.
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.
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.