Avalanche Forecast

Archived

Dec 12th, 2023–Dec 13th, 2023

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

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.

Regions

Cariboos, North Columbia, Clearwater, Quesnel, Jordan.

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, numerous natural dry and wet loose avalanches up to size 1.5 were reported. Older wind slabs up to size 2 were also reported. We suspect they were from the previous storm.

Natural avalanche activity has tapered, but human-triggered avalanches remain likely at higher elevations. Consider the potential for remotely-triggering slopes above and adjacent to you.

Snowpack Summary

The recent 30 to 50 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 1800 m to 2200 m throughout this region.

A concerning layer of surface hoar is now buried 60 to 90 cm deep at upper elevations.

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 100 cm. Snowpack tapers rapidly as you move lower in elevation.

Weather Summary

Tuesday night

Mainly cloudy. Alpine wind 20-30 km/h from the south. Alpine temperatures around 0 C with an alpine temperature inversion, are expected to last for 12-15 hours. Freezing level valley bottom.

Wednesday

Mainly cloudy. Alpine wind 15 to 30 km/h from the south. Alpine temperatures are near +1 C and the freezing level sits near 1000 m. Alpine inversion.

Thursday

Cloudy with snowfall, 5 to 15 cm of accumulation. Alpine wind 10 to 15 km/h from the southwest. Alpine temperature around -3 C. Freezing levels 1300 m.

Friday

A mix of sun and cloud. Alpine winds are light from the south with temperatures near -4 C. Freezing levels 900 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 conservative route selection and resist venturing out into complex terrain.
Be aware of the potential for larger than expected storm slabs due to the presence of buried surface hoar.
Stay off recently wind loaded slopes until they have had a chance to stabilize.

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.