Avalanche Forecast
Issued: Dec 13th, 2023 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Storm Slabs and Persistent Slabs.
swerner,
Avalanche Canada
Recent storm snow and buried weak layers may be reactive to human triggering. Make conservative terrain choices.
Summary
Confidence
Moderate
Avalanche Summary
Since the weekend several skier-triggered persistent slab avalanches up to size 2.5 have been reported. They failed on weak layers comprised of surface hoar and or facets 40-70 cm. Check out this MIN from the adjacent region. It paints a clear picture.
Natural avalanche activity may spike with new snow and strong winds in the forecast, although human-triggered persistent slabs remain the primary concern.
Snowpack Summary
New snow expected on Thursday will bury a variety of snow surfaces including wind-affected snow, sun crusts on steeper south aspects and surface hoar. Approximately 25 to 40 cm down exists 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. This layer has recently been reactive to human triggering above 2100 m.
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 100 to 150 cm. Snowpack tapers rapidly as you move lower in elevation.
Weather Summary
Wednesday NightCloudy with new snow 5-10 cm. Ridgetop wind 15 to 65 km/h from the south. Alpine temperatures near -5 C. Freezing levels valley bottom.
ThursdayCloudy with snowfall, 10 to 15 cm. Ridgetop wind 15 to 25 km/h from the southwest. Treeline temperature around -4 C. Freezing levels valley bottom.
FridayA mix of sun and cloud. Ridgetop wind 15-25 km/h. Treeline temperatures near -5 C and freeing levels valley bottom. Alpine winds are light from the south with temperatures near -2 C. Freezing levels 1200 m.
SaturdayMix of sun and cloud. Ridgetop wind is primarily light with strong gusts. Treeline temperatures near -4 and freezing levels valley bottom. A weak above-freezing layer may occur.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Use careful route-finding and stick to moderate slope angles with low consequences.
- Be aware of the potential for larger than expected storm slabs due to the presence of buried surface hoar.
- Carefully assess open slopes and convex rolls where buried surface hoar may be preserved.
Problems
Storm Slabs
New snow and wind may build reactive storm slabs, especially on northerly aspects where slopes see more loading and deeper slabs.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Persistent Slabs
Buried surface hoar is most likely to be found at treeline and alpine elevations. Human triggering is most likely where the recent rain crust thins, or disappears at higher elevations.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Dec 14th, 2023 4:00PM
