Avalanche Forecast

WEDNESDAY NIGHT: Cloudy / light south wind / ridgeline temperature low -9 / freezing level dropping to valley bottom

THURSDAY: Cloudy with incoming flurries, 5-15 cm accumulation through the day / moderate southerly wind / alpine temperature high -6 / freezing level below 600 m

FRIDAY: Snow, 10-20 cm / moderate gusting to strong southwesterly wind / alpine temperature high -6 / freezing level about 700 m

SATURDAY: Flurries, 5-10 cm / moderate southwesterly wind / alpine temperature high -8 / freezing level around 700 m

On Tuesday, sluffing and thin soft slabs were reactive to skiers on north and east aspects, and pinwheeling and loose-dry avalanches were observed in steep and solar features.

On Monday. A size 2 persistent avalanche was triggered by a skier on the west side of Blackcomb Peak, the crown ranged from 5-90 cm and failed on facets. A size 1.5 windslab was remote triggered on the northwest face of Oboe. Additionally, numerous dry-loose avalanches were observed up to size 2, many running far and entraining large amounts of snow. Wet-loose avalanches failed naturally and were reactive to skiers Monday afternoon.

Sunday was a much quieter day for avalanche activity. Avalanche control work produced very small avalanches with the exception being a single size 2.

A fatal avalanche occurred in the region on Saturday in the Brandywine valley. The person caught was carried several hundred meters over steep, rugged terrain and through treed slopes below. The avalanche is described as a size 1 (small) wind slab on a southwest aspect at 1700 m. The incident report can be seen here.

On Friday, a large (size 2.5), fatal avalanche was triggered by skiers at 2200 m on a west-facing slope on Phalanx Mountain. The avalanche is described as a wind slab that formed to the lee of recent strong east winds. Two people out of a group of three were involved in the avalanche and one person was killed. The incident report can be seen here. A second, smaller (size 1.5) wind slab was triggered by skiers on a nearby slope, again causing injury to the person involved.

A bout of strong northerly winds last Thursday caused conditions in the region to change rapidly, with new and touchy wind slabs forming in unusual places. Numerous natural releases from size 1 to size 2 were observed in the Whistler area above about 1900 m on and since last Thursday. 

A dusting of flurries adds to 10-30 cm loose snow over a variety of wind affected surfaces and facets in the alpine and into treeline. Isolated windslabs remain reactive from recent outflow winds. Fresh southerly winds are impacting loose snow, forming thin new windslabs and hiding older, stiffer slabs.

Below 1800m and on solar features at higher elevations, a thin melt-freeze crust is under the new flurries.

Below the evolving surface, 50-100 cm of settled storm snow sits on a persistent weak layer from late January that consists of facets at upper elevations, surface hoar in sheltered areas, a melt-freeze crust below 1900 m, and a sun crust on south-facing slopes. There could be more than 100 cm on this layer in wind loaded areas. Although this structure is suspect, we have no recent reports of avalanches failing at this interface within the region.

A crust from early December, currently considered dormant, may be found around 200+ cm deep in the snowpack.

• Pay attention to the wind, once it starts to blow fresh sensitive wind slabs are likely to form.
• Recent wind has varied in direction so watch for wind slabs on all aspects.
• Be aware of highly variable recent wind loading patterns.
• Pay attention to cornices and give them a wide berth when traveling on or below ridges.
• Recent new snow may be hiding windslabs that were easily visible before the snow fell.