Warm temperatures are set to undermine stability over the coming days. The strength of our storm slab will be tested on Tuesday. Don't let the sunny weather lure you into inappropriate terrain.
Weather Forecast
Tuesday: Sunny with cloudy periods. Winds light to moderate from the southwest. Freezing level to 3400 metres with alpine temperatures around +5.Wednesday: Mainly cloudy. Winds strong gusting to extreme from the southwest. Freezing level dropping from 3000 to 2000 metres with alpine temperatures around +4.Thursday: Flurries bringing about 5 cm of new snow. Winds strong gusting to extreme from the southwest. Freezing level around 2000 metres with alpine temperatures of +2.
Avalanche Summary
Sunday's reports are limited to a single MIN post revealing an impressive Size 3 avalanche in the Little Sands area. This avalanche -along with a number of others observed the same day- appears to have been triggered by solar warming. While the age of the avalanche in the photo is uncertain, backcountry travelers should be ready for ongoing warming to produce these types of avalanches over the coming days.Before this warming took effect, explosives control work in the Fernie area on Saturday yielded a few results up to to Size 1 within wind-affected surface snow. Friday's control work produced numerous storm slab results generally from Size 2-2.5 with two Size 3 results generating from storm loaded north to northeast aspects.
Snowpack Summary
Strong ridgetop winds have led to roughly 10 cm of wind scoured and pressed new snow at the surface, leaving very little in the way of ski penetration at treeline and above. Below around 1700 metres, the supportive, wind-affected snow gives way to a breakable rain crust. Beneath these variable surfaces lies an estimated metre of storm snow from storms over the past two weekends. The upper half of this layer was deposited as heavy, moist snow, while the lower half is considerably drier and less dense. This 'upside down' storm snow layer lies above a range of previous surfaces that includes wind affected surfaces, a layer of surface hoar in sheltered areas, facets, and/or a thin sun crust. The bond between this earlier storm snow and the old surface is suspected to be improving slowly while hard conditions at the current surface may be diminishing the effect of human triggering. The mid and lower snowpack are generally well settled and stable but isolated basal weaknesses may exist in shallow snowpack areas.
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.
Wind Slabs
Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind 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.
Loose Wet
Loose Wet avalanches are the release of wet unconsolidated snow or slush. These avalanches typically occur within layers of wet snow near the surface of the snowpack, but they may quickly gouge into lower snowpack layers. Like Loose Dry Avalanches, they start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-wet avalanches include point-release avalanches or sluffs. Loose Wet avalanches can trigger slab avalanches that break into deeper snow layers.