Regions
Kootenay Boundary.
Wind slabs continue to be reactive to human triggers, especially on south-southwesterly aspects at treeline and above.
Confidence
High - The weather pattern is stable
Weather Forecast
SUNDAY: Mainly sunny / light east wind / alpine temperature -13 CMONDAY: Mainly sunny / light to moderate east wind / alpine temperature -10 CTUESDAY: A mix of sun and cloud / light to moderate east wind / alpine temperature -7 C
Avalanche Summary
On Saturday reports indicate a few size 1-1.5 wind slab avalanches on west aspects in the alpine and treeline. There were reports of several size 1-1.5 explosives triggered storm slab avalanches on Friday in the alpine and tree line on northerly aspects. On Thursday, dry loose sluffing was seen in steeper terrain features.
Snowpack Summary
The surface consists of 15-30 cm of low density new snow. This new snow may have a poor bond to the previous firm wind slabs and faceted (sugary) snow surfaces. A layer of feathery surface hoar sitting on a crust that was buried on February 7th is now 30-50 cm deep. Two other surface hoar layers are buried 50 to 80 cm down (referred to as the February 1st and mid-January layers) remain reactive in snowpack tests.
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.
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.