Avalanche Forecast

Archived

Nov 24th, 2023–Nov 25th, 2023

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely.

Below Treeline

Natural avalanches unlikely.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely.

Below Treeline

Natural avalanches unlikely.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely.

Below Treeline

Natural avalanches unlikely.

Regions

Northwest Coastal, Stewart, Ningunsaw, Ningunsaw.

Limited observations and the potential for large human-triggered avalanches necessitate a conservative start to the season.

Confidence

Low

Avalanche Summary

During the storm last week, numerous natural wind slab and persistent slab avalanches were reported up to size 3 in Ningunsaw and Bear Pass.

Natural avalanche activity tapered with the storm. No new avalanches have been reported in the past few days.

Observations are very limited at this time of year. If you do head out, do so with a cautious and investigative mindset, and consider submitting a MIN report.

Snowpack Summary

40-70 cm of recent storm snow has been redistributed into wind slabs in the alpine and treeline. Surface conditions otherwise have been reported as 10-15 cm of dry snow overlying a series of crusts or moist snow.

Observations are limited, but a problematic crust/facet combination exists near the base of the snowpack in the Bear Pass and Ningunsaw area (likely elsewhere too). With total snowpack depths around 150 cm at 1000m, this layer is a concern for human triggering, particularly in shallow or variable depth snowpack areas in the alpine.

Weather Summary

Friday night

Cloudy with light rain, northwest alpine wind 30 to 60 km/h, treeline temperature 0°C.

Saturday

Mostly cloudy with a chance of light rain, northwest alpine wind 15 to 35 km/h, treeline temperature 0°C, freezing level 1100 m.

Sunday

Mostly cloudy with light flurries, southwest alpine wind 30 to 60 km/h, treeline temperature -2°C.

Monday

Cloudy with 1-5 cm of snow, southwest alpine wind 40 to 70 km/h, treeline temperature -2°C.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

Make observations and assess conditions continually as you travel.
Avoid steep, rocky, and wind effected areas where triggering slabs is more likely.
Avoid areas where the snow feels stiff and/or slabby.

Problems

Wind Slabs

Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.

Persistent Slabs

Persistent Slab avalanches are the release of a cohesive layer of snow (a slab) in the middle to upper snowpack, when the bond to an underlying persistent weak layer breaks. Persistent layers include: surface hoar, depth hoar, near-surface facets, or faceted snow. Persistent weak layers can continue to produce avalanches for days, weeks or even months, making them especially dangerous and tricky. As additional snow and wind events build a thicker slab on top of the persistent weak layer, this avalanche problem may develop into a Deep Persistent Slab.