Avalanche Forecast

Archived

Dec 12th, 2023–Dec 13th, 2023

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches unlikely.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches unlikely.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Regions

Blue River, McBride, Premier, Clemina, Esplanade, North Monashee, North Selkirk.

Reduce your exposure to avalanche terrain if the temperature is above 0°C. Make conservative terrain choices. Recent storm snow and buried weak layers may be reactive to human triggering.

Confidence

Moderate

Avalanche Summary

On Monday, in the Esplanades, skiers remote-triggered two persistent slab avalanches (size 1 and size 2) in alpine terrain. A skier-triggered wind slab size 2 was reported outside of the ski hill boundary at RMR. Check out the MIN post here.

Natural avalanche activity has tapered, but human-triggered avalanches remain possible at higher elevations, particularly where slabs sit over the weak surface hoar.

Snowpack Summary

The recent 30-40 cm of storm snow has likely been redistributed into deeper deposits on north and east facing slopes at higher elevations. This sits over a rain crust that has been observed to ridgeline in most areas.

A concerning layer of surface hoar is now buried 50-80 cm deep.

The lower snowpack is a mix of rounded and faceted grains. A hard crust may be found near the ground.

Treeline snowpack depths are variable and generally range between 60 and 140 cm. Snowpack tapers rapidly as you move lower in elevation.

Weather Summary

Tuesday night

Mainly clear. Alpine wind 20-30 km/h from the southeast. Alpine temperatures around -1 C with an alpine temperature inversion, expected to last for 12-15 hours. Freezing level valley bottom.

Wednesday

Mix of sun and cloud. Alpine wind 15 to 30 km/h from the southwest. Alpine temperatures near -1 and the freezing level sits near 1400 m.

Thursday

Cloudy with snowfall, 5 to 15 cm of accumulation. Alpine wind 10 to 15 km/h from the southwest. Treeline temperature around -5 C. Freezing levels 1300 m.

Friday

A mix of sun and cloud. Alpine winds are light from the south with temperatures near -2 C. Freezing levels 1200 m.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

Extra caution for areas experiencing rapidly warming temperatures for the first time.
Use careful route-finding and stick to moderate slope angles with low consequences.
Carefully assess open slopes and convex rolls where buried surface hoar may be preserved.

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.