http://www.pc.gc.ca/apps/scond/Cond_E.asp?oID=19299&oPark=100092For specific comments on the opening of Whistler and Portal Creek on Monday - go to the snowpack discussion within the forecast details section.
Weather Forecast
Colder conditions, little in the way of precipitation and light NW winds should do little to change the present avalanche hazard. With all the wild swings in temperature and precipitation types this winter, the snowpack is a complex layer of slabs, crusts, old surface hoar and facets which demands respect from those venturing into the mountains.
Snowpack Summary
Whistler and Portal Creek are open on Monday but tourers should be mindful that this area has seen no ski traffic and only limited field observations. Given the complexity of the snowpack and the occurrence of some very large avalanches, back-country travelers are advised to be conservative in their choice of terrain throughout the forecast area.
Avalanche Summary
There has been a natural avalanche cycle in the last 48 hours with numerous size 2 and 3 slab avalanches at treeline and alpine elevations, many stepping down to the early season basal facets/crust layer. The most notable slide was a full path size 3.5 on the South Churchill Slide path whose crown wall extended for over 800m.
Problems
Deep Persistent Slabs
Deep Persistent Slab avalanches are the release of a thick cohesive layer of hard snow (a slab), when the bond breaks between the slab and an underlying persistent weak layer deep in the snowpack. The most common persistent weak layers involved in deep, persistent slabs are depth hoar or facets surrounding a deeply buried crust. Deep Persistent Slabs are typically hard to trigger, are very destructive and dangerous due to the large mass of snow involved, and can persist for months once developed. They are often triggered from areas where the snow is shallow and weak, and are particularly difficult to forecast for and manage.
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.