Archived

Avalanche Forecast

Dec 26th, 2018–Dec 27th, 2018

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

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

2: Moderate

The avalanche danger rating below treeline will be moderate

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

3: Considerable

The avalanche danger rating below treeline will be considerable

Regions: Northwest Coastal.

Fresh snow and wind will continue to form slabs at upper elevations and in wind-loaded features. Expect wind slabs to be more prevalent in lee-features, cross-loaded terrain, and open areas.

Confidence

Low - Due to the number of field observations

Weather Forecast

WEDNESDAY NIGHT: Cloudy with flurries, trace to 10 cm accumulation. Moderate southwest wind. Freezing level below 600 m.THURSDAY: Periods of snow, 5-15 cm accumulation. Light to moderate south-southwest wind. Freezing level 600 m.FRIDAY: Snow, 15-35 cm accumulation. Moderate south-southwest wind with strong to extreme gusts. Freezing level rising above 1000 m.SATURDAY: Periods of snow, 10-45 cm accumulation. Moderate gusting strong west-southwest wind. Freezing level dropping below 1000m.

Avalanche Summary

On Sunday, explosives were able to trigger wind slab avalanches to size 1.5. Additionally, a large (size 2) natural wind slab avalanche was observed on a northeast aspect. On Monday, wind-loaded pockets were reactive to skier traffic, including 2 very small unsupported pockets remotely triggered (from a distance) by skiers.Information from this region is limited. Tell us what you see by posting to the Mountain Information Network MIN.

Snowpack Summary

Up to 20 cm of new snow sits on a melt-freeze crust at elevations below approximately 1000 m. Above 1000 m, this new snow is just adding to the 150+ cm of recent snowfall from over a week ago. Moderate to strong winds have redistributed recent snow and formed wind slabs at upper elevations, especially in lee and cross-loaded features. Expect to find more reactive slabs in wind loaded areas, and especially in places that receive higher snowfall amounts.A total 120-200 cm of mid-December snow sits on a weak layer of surface hoar (feathery crystals), facets (sugary snow), and crusts. This layer was initially a concern when snowfall first accumulated, but the strength of this layer has generally improved. The surface hoar is most prevalent and has most recently been reactive between 1100-1300 m in more northern portions of the region, and is something to keep in mind if you plan to travel to areas like Ningunsaw.Deeper in the snowpack, there are several crusts, including an early season crust with facets near the bottom of the snowpack.

Avalanche Problems

Wind Slabs

Recent snow continues to be redistributed by winds and form slabs. Deeper and more sensitive wind deposits are likely found at higher elevations, these are the most suspect for human triggering.

Be careful with wind loaded pockets, especially near ridge crests and roll-overs.Pay attention to overhead hazards like cornices which could easily trigger persistent slabs.Be cautious as you transition into wind affected terrain.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Possible - Likely

Expected Size: 1 - 2