Avalanche Forecast

Archived

Jan 29th, 2024–Jan 30th, 2024

Alpine

Natural and human triggered avalanches likely.

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, human triggered possible.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Regions

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

Avoid being in or under alpine avalanche terrain. Stormy conditions continue in much of the forecast area.

Expect conditions to change drastically with elevation.

Confidence

Moderate

Avalanche Summary

On Sunday, several large to very large (up to size 3) slab avalanches were reported, along with numerous, large (up to size 2) loose wet avalanches during the rain.

On Tuesday, we expect that natural and human triggered avalanches will remain likely in places that are seeing rapid loading of new snow.

At elevations that are still receiving rain, avalanches will be less likely, and smaller.

Snowpack Summary

Moderate snow and rain are expected overnight Monday and through the day on Tuesday. 20-35 cm of snow expected in the alpine. This likely covers dense, moist snow. At treeline and below, expect to find heavy, moist or wet snow on the surface, becoming very slushy at low elevations.

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

Monday Night

Cloudy. 20 cm of snow expected above 1000 m. Moderate southeast ridgetop wind trending to strong southwest by the morning. Treeline high around 1 °C.

Tuesday

Cloudy. 5-15 cm of snow expected above 1200 m. Strong southwest ridgetop wind. Treeline temperature around 0 °C.

Wednesday

Cloudy. LIght rain expected, up to 10 cm of snow above 2000 m. Strong southeast ridgetop wind. Treeline temperature around 3 °C.

Thursday

Cloudy. Light rain expected, up to 10 cm of snow above 1500 m. Moderate southeast ridgetop wind. Treeline temperature around 1 °C.

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.
The more the snow feels like a slurpy, the more likely loose wet avalanches will become.
Make observations and assess conditions continually as you travel.

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.