Archived

Avalanche Forecast

Nov 25th, 2022–Nov 26th, 2022

Alpine

2: Moderate

The avalanche danger rating in the alpine will be moderate

Treeline

2: Moderate

The avalanche danger rating at treeline will be moderate

Below Treeline

1: Low

The avalanche danger rating below treeline will be low

Alpine

4: High

The avalanche danger rating in the alpine will be high

Treeline

3: Considerable

The avalanche danger rating at treeline will be considerable

Below Treeline

1: Low

The avalanche danger rating below treeline will be low

Alpine

3: Considerable

The avalanche danger rating in the alpine will be considerable

Treeline

2: Moderate

The avalanche danger rating at treeline will be moderate

Below Treeline

1: Low

The avalanche danger rating below treeline will be low

Regions: Brandywine.

Snowfall accumulation and wind will intensify throughout the day. Expect to find increasingly reactive slabs in wind-loaded areas and plan to get home before the storm really hits.

Confidence

Moderate

Avalanche Summary

On Thursday, a small wind slab was triggered by a skier on a northeast ridge feature, explosives work on cornices triggered small (size 1) slabs on the slopes below, and wet loose avalanches were observed in steep rocky terrain below 1900 m.

On Wednesday, explosive control work in the Whistler area produced several storm slab avalanches up to size 2 in the alpine and upper treeline. These avalanches occurred in wind-loaded terrain.

Looking forward, we expect slabs to become increasingly reactive as snowfall accumulates, first in wind-loaded areas and then becoming widespread by Sunday morning.

Snowpack Summary

On Friday wind and warm temperatures quickly impacted up to 15 cm fresh snow. Accumulation totals quickly tapered with elevation.

A weak drought layer is down 20-50 cm. This layer consists of hard, wind-affected snow in the alpine, surface hoar or facetted snow in sheltered areas, and a crust on solar aspects and on all aspects below 2200m. Below this layer, several other facet-crust interfaces exist in the snowpack.

Typical snow depth ranges from 80-150 cm in the alpine and 50-70 cm at treeline. Expect early season conditions and rugged travel. Below treeline is below the threshold for avalanches.

Weather Summary

Friday night

Cloudy with isolated flurries, trace accumulation. Light west wind increasing overnight, treeline temperatures below -5 C, freezing level dropping below 1000 m.

Saturday

Snowfall and wind will intensify throughout the day. Up to 15 cm accumulating by 4 pm Saturday as southwesterly winds increase into extreme. Alpine high -4 C. Freezing level around 1200 m.

Sunday

Heavy snowfall and extreme winds are expected overnight, with up to 35 cm of new snow by morning. Convective flurries may continue through the day. West wind decreasing to moderate through the day, treeline temperatures dropping to -10 C, and freezing level dropping to valley bottom.

Monday

Cold with a mix of sun and cloud. Light to moderate southerly wind, treeline lows down to -18 C, and freezing level valley bottom.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

Storm snow and wind is forming touchy slabs. Use caution in lee areas in the alpine and treeline.
Dial back your terrain choices if you are seeing more than 25cm of new snow.

Avalanche Problems

Wind Slabs

Snowfall accumulation and wind will intensify throughout the day. Expect to find increasingly reactive slabs in wind-loaded areas, this will develop into a widespread storm slab problem by Sunday morning.

Aspects: North, North East, East, South East, North West.

Elevations: Alpine, Treeline.

Likelihood: Possible

Expected Size: 1 - 2