Please Note That Backcountry Refers To Any Areas Outside The Ski Area Boundary
This three day avalanche hazard forecast is prepared for the area immediately surrounding Whistler Blackcomb - terrain easily accessible as a day tour from WB’s boundaries. In contrast, the Canadian Avalanche Centre posts avalanche advisories are for the Sea to Sky corridor; ranging from ‘the Duffey’ to the Fraser Valley. See their advisories here: avalanche.ca/cac/bulletins/latest
There is a lingering buried persistent weakness that has been presenting itself as a low probability but high consequence problem. Increasing loads will continue to stress this layer. The new and storm snow slabs may be reactive in the alpine and moist sluffing will likely occur at treeline elevations.
Avalanche Canada issued a Special Avalanche Warning for the Sea to Sky corridor including the Whistler Blackcomb Backcountry. Although the warning has expired, the message remains appropriate. With the warming today, there is an increased likelihood of triggering large slab avalanches. You need to be very aware of overhead hazards such as cornices and large slopes.
Some minor snowballing occurred yesterday as temperatures warmed. Explosive testing in the morning produced some soft slabs. Throughout the week in the backcountry, numerous slab avalanches from size 1.5 to 3 were triggered naturally, remotely and by light loads in lee and cross loaded terrain features. There have been reports of whumphing and settlements as well. You can expect to see moist sluffing and snowballing at treeline today.
The overnight snowfall was accompanied by warming temperatures, and the rainline is now at about 1700m. These new and storm snow layers overlie the 10-100cm of wind and storm slabs on top of the March 11th facet/crust interface. The slab depth seems to max out on northerly aspects. Snowpack tests have yielded easy and moderate planar shears at the interface of this persistent weakness. You can expect that it will likely linger for some time to come.
An approaching cold front will bring periods of snow later today and tonight. Conditions will remain cool and unsettled into the middle of the week.
Watch out for winch-cats or snowmobile traffic if you re-enter the area after operating hours.
Whistler Mountain Snow Safety
Every backcountry user should be well prepared and travel with experienced backcountry users. Each member should carry an avalanche transceiver on the 457 KHz frequency and carry equipment for self-rescue.
Our avalanche advisory is updated regularly during the winter season from November through to June. Our hours of operation page has opening and closing dates and times for our winter season. Whistler Mountain's avalanche forecasters post bulletins updating the status and stability of the snow in the backcountry based on snow surveys taken from both within and outside the ski area boundaries.
Be aware that conditions may change and sometimes vary from one slope to the next.