Weather Forecast
Synopsis: A very strong ridge of high pressure continues to dominate the weather pattern with no end in sight.Monday: Sky: Mix Sun/Cloud; Freezing Level: Valley Bottom; Precip: Nil Wind: Light, NE, Mod NE at ridgetop.Tuesday: Sky: Mix Sun/Cloud; Freezing Level: Valley Bottom; Precip: Nil Wind: Light, NEWednesday: Sky: Mix Sun/Cloud; Freezing Level: Valley Bottom; Precip: Nil Wind: Light, NE, Mod NE at ridgetop.
Avalanche Summary
In two separate incidents, skiers triggered small wind slab avalanches on north & east facing aspects around 2000m. Deep Persistent Slabs have been removed from the problem portion of the forecast because it's probably a 1:1000 slope event at this time, but they haven't totally gone away. Two large natural avalanches (size3) were observed on a steep south facing alpine feature south of Revelstoke.
Snowpack Summary
The upper and mid-snowpack are generally well consolidated and layers are well bonded. However, in thinner snowpack areas a facet/crust weakness may exist near the bottom of the snowpack and this remains a concern. The depth of this layer makes triggering an avalanche unlikely but the consequences would be large, destructive avalanches. This is referred to as a 'low probability, high consequence' event. We are recommending avoiding thin or rocky areas on steep, convex, unsupported slopes. In most areas, a widespread weak layer is now buried by around 10cm of new snow. This weak layer consists of large surface hoar (widespread in most sheltered and shaded areas at all elevations), a sun crust on open south facing slopes, facet grains (in colder areas or areas with a thinner snowpack), or a combination of any of the above. This layer may become a problem in the future when we finally get more snowfall.
Problems
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 Dry
Loose Dry avalanches are the release of dry unconsolidated snow and typically occur within layers of soft snow near the surface of the snowpack. These avalanches start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-dry avalanches include point-release avalanches or sluffs.