Avalanche Forecast

Archived

Jan 30th, 2024–Jan 31st, 2024

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, 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.

Continue to make conservative terrain choices.

We are transitioning out of a warm, stormy period that introduced rapid change to the snowpack.

Confidence

Moderate

Avalanche Summary

On Sunday, and into Monday morning, numerous large to very large (up to size 3) naturally triggered storm slab, wet slab, and loose wet avalanches were reported. These likely occurred during the most intense parts of the storm. No new avalanches were reported before 4 pm on Tuesday.

Looking forward to Wednesday, we expect that natural avalanches like this will be much less likely, but human-triggered avalanches will remain likely.

Snowpack Summary

Light snow and rain are expected through the day on Wednesday. This likely covers dense, moist snow or a refrozen crust. 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. The recent storm snow/rain and warm temperatures triggered large avalanches on these layers during the height of the storm, but it is expected that they will start to strengthen with calmer, cooler weather.

Weather Summary

Tuesday Night

Possible clear periods in the evening, cloudy by the morning. 2-4 cm of snow expected above 500 m. Moderate southeast ridgetop wind. Treeline temperature around 0 °C.

Wednesday

Cloudy. Light rain expected, up to 10 cm of snow above 1750 m (heavier rain and snow near Kitimat). Moderate to strong south or southeast ridgetop wind. Treeline temperature around 2 °C.

Thursday

Mostly cloudy. Light rain expected, 5-10 cm of snow above 1500 m. Moderate south or southeast ridgetop wind. Treeline temperature around 1 °C.

Friday

Partly cloudy. 3-7 cm of snow expected to near valley bottom. Moderate to strong southwest ridgetop wind. Temperature dropping rapidly, treeline low around -8 °C.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.
Make observations and assess conditions continually as you travel.
The more the snow feels like a slurpy, the more likely loose wet avalanches will become.

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.

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.