Spring Conditions. The ridge of HIGH pressure is breaking down, and a weak weather system is moving on-shore. Expect high freezing levels to continue to result in wet slab and loose wet avalanches.
Avalanche problems
Cornices
N
NE
E
SE
S
SW
W
NW
Alpine
Treeline
Below treeline
Likelihood
Possible
Size
2–5
Cornices may continue to fall off naturally during periods of high freezing levels and warm daytime temperatures. Cornice falls may trigger wet slab avalanches.
Loose Wet
N
NE
E
SE
S
SW
W
NW
Alpine
Treeline
Below treeline
Likelihood
Likely
Size
1–3
Loose wet avalanches may continue due to one more day of high daytime freezing levels. If it rains before the surface re-freezes, loose wet avalanches will be very likely.
Wet Slabs
N
NE
E
SE
S
SW
W
NW
Alpine
Treeline
Below treeline
Likelihood
Possible
Size
3–6
Wet slab avalanches continue to be a concern due to strong solar radiation and high daytime freezing levels. Forecast cloud may decrease the likelihood once the freezing levels drop and new surface crusts form.
Weather Forecast
High cloud developing overnight with light southerly winds and freezing levels down to 2000 metres. Light precipitation starting Thursday morning combined with light southwest winds and freezing levels rising up to 2500 metres. Cloudy on Friday with 3-5 cm of new snow above 2000 metres and light southwest winds. Continued overcast with light precipitation and light winds on Saturday.
Avalanche Summary
On Tuesday a size 3.0 wet slab avalanches was explosives triggered in the Duffey Lake area, this large avalanche released down to the ground on a northwest aspect at 2200 metres and ran to the valley bottom. Most commercial operations in the region have finished their season and data is sparse.
Snowpack Summary
Cornices are large, fragile, and could trigger deep slab avalanches that run to valley bottoms. Monitoring the overnight freeze of the snow surface is very important.. If the snow surface does not freeze overnight or if the crust is only a few cm thick, the effect of daytime heating and solar radiation will weaken the snowpack much quicker. There is an old crust layer down approximately 50cm in the Duffey area and north of Pemberton. Though mostly dormant, it produced a couple large avalanches during the last major warming event. The forecast hottest weather of the year to date could again test it, especially in isolated locations such as steep, rocky faces. Glide cracks are widespread, active, and best avoided. Low elevation and thin snowpack areas have become isothermal, meaning the snowpack is 0 degrees Celsius throughout. An isothermal snowpack is more prone to full depth wet slab avalanches during the heat of the day, especially on steep, smooth slopes.