Avalanche Forecast

An offshore low pressure system is bringing cooler temperatures and flurries with variable amounts of new snow.

THURSDAY NIGHT: Scattered flurries with variable accumulations of new snow (5-15 cm), 40-50 km/h south wind, treeline temperatures around -4 C with freezing level dropping to 1000 m.

FRIDAY: Scattered flurries continue with another 5-15 cm possible, resulting in 24 h accumulations between 5-30 cm, 40-60 km/h south wind, treeline temperatures around -6 C with freezing level around 1000 m.

SATURDAY: Flurries end by the morning then a mix of sun and cloud, 20-30 km/h southwest wind, treeline temperatures around -2 C.

SUNDAY: 5-10 cm of snow, 30-50 km/h south wind, treeline temperatures around -6 C.

Cornices were triggered by explosives on Monday to Thursday, releasing large chunks that could kill a person but they did not trigger slabs. Avalanche activity is expected to increase in the coming days as a series of storms impact the region.

There's been some large avalanches in the past week around the Whistler area, including one on a north aspect on Cloudburst Mountain, some near Mt. Fee (see here and here), and one last week on Mt. Fissile in the Whistler backcountry. These avalanches may be due to extensive wind loading, but they may also be associated with isolated weak snow from earlier this season.

Snow accumulations are expected to be highly variable across the region on Friday, and will likely increase dramatically with elevation. Storm slabs will be reactive anywhere sufficient snow accumulates, especially on northerly aspects that will receive extra wind loading. The new snow will overly a melt-freeze crust up to around 1600 m and higher on sun-exposed slopes or wind-affected dry snow on northerly aspects at high elevations. Remember that cornices along ridgelines are large at this time of year and always have the possibility of failing naturally or from the weight of a human.

Around 100 to 300 cm of consolidated snow may overly sugary faceted grains formed earlier this season. These layers are expected to be spotty around the region and we haven't received conclusive evidence of them being the culprit of avalanche activity. That being said, it is possible they may be associated with a few recent large avalanches around the Whistler area.

• Avoid freshly wind loaded terrain features.
• Watch for signs of slab formation throughout the day.
• Dial back your terrain choices if you are seeing more than 20 cm of new snow.
• Look for signs of instability: whumphing, hollow sounds, shooting cracks, and recent avalanches.