Natural avalanches unlikely, human triggered possible.
Treeline
Natural avalanches unlikely, human triggered possible.
Below Treeline
Natural avalanches unlikely, human triggered possible.
Alpine
Natural avalanches unlikely, human triggered possible.
Treeline
Natural avalanches unlikely, human triggered possible.
Below Treeline
Natural avalanches unlikely, human triggered possible.
Alpine
Natural avalanches unlikely, human triggered possible.
Treeline
Natural avalanches unlikely, human triggered possible.
Below Treeline
Natural avalanches unlikely, human triggered possible.
Regions
South Coast Inland.
New and loose snow will hide older, hard wind slabs and build new ones. The largest deposits, and potentially the most reactive, will be found in wind-loaded terrain.
Confidence
Moderate - Intensity of incoming weather systems is uncertain
Weather Forecast
TUESDAY NIGHT: Cloudy with clear periods and isolated flurries, trace to 10 cm accumulation with the largest amounts near Allison Pass and the Coquihalla. Alpine temperatures near -16C. Ridgetop winds light from the northeast.WEDNESDAY: Cloudy with sunny breaks. Alpine temperature near -11C. Ridgetop winds light from the southeast-east.THURSDAY: Mix of sun and cloud with isolated flurries, trace to 10 cm accumulation with the largest amounts near Allison Pass and the Coquihalla. Alpine temperatures near -7C, temperatures may rise significantly with the incoming system. Ridgetop winds light from the east.FRIDAY: Cloudy with sunny periods and isolated flurries, trace to 10 cm accumulation. Alpine temperatures near -9C. Ridgetop winds light gusting moderate from the southwest.
Avalanche Summary
Weekend reports from the Duffy and Joffre Lakes area document stiff wind slabs easily triggered by skiers including size 2 skier triggered wind slab avalanches. The larger skier triggered avalanches are being reported on north-northeasterly alpine features (see the Tszil MIN report here).
Snowpack Summary
A dusting of new snow fell on variable wind-pressed, wind-sculpted, exposed crust and windslab surfaces covering alpine and higher treeline elevations. as a result of the recent extreme wind event. Additionally, the extreme winds deposited snow lower in start zones than usual and developed wind slabs in more protected areas and at lower elevations.Due to scouring and wind-loading, anywhere from 0-60 cm of new snow and old, wind-affected snow sits on a crust on all aspects below 2000m and solar aspects into the alpine. Above 1800 m, recent cold temperatures have been working to facet and break down the buried crust. In isolated and sheltered terrain at treeline and below, a layer of weak feathery surface hoar or sugary facets may be identified, but with little reactivity. Below the new snow, wind-affected snow and crust, another crust is found down 50-80 cm that formed mid-January right to mountain top on southerly aspects and on all aspects below 1700 m. Additionally at this depth, feathery surface hoar may be found in shady sheltered areas at treeline, but with little reactivity.The remainder of the snowpack is generally well-settled.
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.