Avalanche Forecast

Archived

Dec 26th, 2023–Dec 27th, 2023

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Regions

Kitimat, Nass, Rupert, Shames.

The quest for good snow requires you to travel high enough to avoid wet snow and frozen crusts, and then dodge wind exposed ridges and cross-loaded gullies.

Good luck, backcountry scouts.

Confidence

Moderate

Avalanche Summary

On Tuesday, between Terrace and the coast, numerous naturally triggered storm slab and wet loose avalanches were reported at treeline and below.

On Monday, in the Shames backcountry, sounds of large avalanches in big terrain were reported. See this MIN (Mountain Information Network) post for more details of what sounded like a soggy day.

If you head into the backcountry please consider submitting your observations to the Mountain Information Network.

Snowpack Summary

Storm snow continues to accumulate daily. At treeline and below, expect to find a layer of wet snow near the surface. Generally strong southerly winds are building wind slabs in exposed leeward terrain. South facing slopes (windward), have likely been scoured by the strong winds or have dense, wind packed snow.

Two buried layers of surface hoar are widespread in the mid snowpack, buried 50-100 cm, and 90-130 cm deep.

The remaining mid and lower snowpack contains several crusts from early in the season that are generally well-bonded to the surrounding snowpack. Snow depths are highly variable depending on elevation, and decrease rapidly below treeline.

Weather Summary

Tuesday Night

Mostly cloudy. 4-8 cm of snow expected. Moderate southwest ridgetop wind, shifting to southeast by the morning. Freezing level falling to near valley bottom, treeline temperatures around -6°C.

Wednesday

Cloudy. 10-20 cm of snow expected above 500 m. Strong southeast ridgetop wind. Treeline temperatures around -2 °C.

Thursday

Cloudy. Moderate rain, snow and freezing rain all possible (10-20 mm). Strong to extreme south ridgetop wind. Treeline temperatures around 1 °C. Possible above freezing layer.

Friday

Cloudy. Moderate rain expected below 1750 m. Strong southeast ridgetop wind. Treeline temperatures around 0 °C.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

Approach lee and cross-loaded slopes with caution.
Recent wind has varied in direction so watch for wind slabs on all aspects.
Approach steep open slopes at and below treeline cautiously, buried surface hoar may exist.

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.