Avalanche Forecast

Archived

Feb 2nd, 2024–Feb 3rd, 2024

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

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

Kootenay Boundary, Bonnington, Grohman, Kootenay Pass, Norns, Rossland, Ymir, Crawford, Kokanee, Retallack, Valhalla.

The good news...❄️ winter is back! ❄️

The bad news... storm snow may not bond well with the crust.

Dial back your terrain choices as storm snow accumulates this weekend.

Confidence

Moderate

Avalanche Summary

Natural avalanche cycles continued throughout this week with rain, warming, and sunshine weakening the upper snowpack. Wet loose and wet slab avalanches (on the facet layer 30-60 cm deep) were reported to size 2.5. Cooling on Thursday and Friday limited further activity.

Moving forward avalanche activity will become more likely as storm snow accumulates.

Snowpack Summary

Up to 10 cm of storm snow is expected to accumulate over Saturday. This will fall over moist snow at low elevations, or over a crust at higher elevations and may not bond well.

A layer of facets (and small surface hoar in some areas) is buried 30-60 cm deep and a layer of facets on a crust is buried 80-100 cm deep. The cooling trend is expected to strengthen these layers, but we are uncertain how quickly this will happen.

Weather Summary

Friday Night

Cloudy with no new snow expected. Light and variable winds. Freezing levels drop to around 1300 m.

Saturday

Cloudy with up to 10 cm of snow expected over the day. Freezing levels remain around 1500 m, with treeline temperatures around -2 °C. 10-30 km/hr easterly winds.

Sunday

By Sunday morning another 10-20 cm is possible. Freezing levels reach 1500 m again. Treeline temperatures around -2 °C. Southeast winds, 10-20 km/h.

Monday

A mix of sun and cloud with flurries is possible. Freezing levels reach 1500 m over the day. Treeline temperatures around -2 °C. Southeast winds 20-40 km/h.

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.
Wind slabs may be poorly bonded to the underlying crust.
Wind slabs are most reactive during their formation.

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.