Avalanche Forecast

Archived

Jan 28th, 2024–Jan 29th, 2024

Alpine

Natural and human triggered avalanches likely.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches possible, human triggered probable.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Regions

Kitimat, Nass, Rupert, Seven Sisters, Shames, Howson.

New snow, warm temperatures, and rain may be overloading buried weak layers. Use extra caution if entering avalanche terrain today.

Confidence

Moderate

Avalanche Summary

Friday: Size 1 and 2 loose wet, and wet slab avalanches were observed in the alpine out of lee features.

Several small (size 1) loose wet avalanches were also observed in the Shames Mountain backcountry.

Thursday: Two small (size 1) natural and rider triggered wet slabs were observed.

Snowpack Summary

10-25 cm of snow and /or rain has fallen in region over the last week. This snow is likely very dense, settling rapidly, and moist or wet at treeline elevations and below, where some of this snow fell as rain.

A layer of surface hoar and facets has been found 30-50 cm deep in parts of the region. Below this sits a 15 cm thick hard crust. There is potential for the accumulated storm snow / rain and warm temperatures to overload these layers triggering large avalanches.

Weather Summary

Sunday Night

Cloudy with 10-15 cm of new snow / moderate rain, south alpine wind 60 km/h, treeline temperature 6°C, freezing level rising to 2200 m

Monday

Cloudy with 10-20 cm of new snow / moderate to heavy rain, southerly alpine wind 70 km/h, treeline temperature 3 °C, freezing level 1600 m.

Tuesday

Cloudy with 3-12 cm snow / light to moderate rain, southwesterly alpine wind 60-70 km/h, treeline temperature 2 °C, freezing level 1200m m.

Wednesday

Cloudy with 3-10 cm snow / light rain, southerly alpine wind 50-60 km/h, treeline temperature 0 °C, freezing level 900 m.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

Avoid all avalanche terrain during periods of heavy loading from new snow, wind, or rain.
Storm slabs in motion may step down to deeper layers resulting in large avalanches.
As surface loses cohesion due to melting, loose wet avalanches become common in steeper terrain.

Problems

Storm Slabs

Storm Slab avalanches are the release of a cohesive layer (a slab) of new snow that breaks within new snow or on the old snow surface. Storm-slabs typically last between a few hours and few days (following snowfall). Storm-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.

Loose Wet

Loose Wet avalanches are the release of wet unconsolidated snow or slush. These avalanches typically occur within layers of wet snow near the surface of the snowpack, but they may quickly gouge into lower snowpack layers. Like Loose Dry Avalanches, they start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-wet avalanches include point-release avalanches or sluffs. Loose Wet avalanches can trigger slab avalanches that break into deeper snow layers.