Avalanche Forecast
Issued: Dec 26th, 2022 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Storm Slabs and Loose Wet.
rbuhler,
Avalanche Canada
Observations have been very limited and there is a lot of uncertainty about how the ongoing storm and rainfall are affecting the snowpack, so a cautious approach is advised. It is recommended to avoid steep rain-soaked areas at lower elevations and watch for new storm slab formation at the highest elevations, especially in wind-loaded terrain.
If you're out in the mountains, please consider submitting a MIN and let us know what you're seeing.
Summary
Confidence
Low
Avalanche Summary
On Sunday, observations remained limited but included several size 1 loose wet avalanches and a size 1.5 wet slab avalanche.
On Saturday, limited observations during the storm included numerous natural loose wet avalanches up to size 1.5 and several natural slab avalanches up to size 2. These slabs were up to 40 cm thick and were typically releasing at around treeline elevation. Some of these slabs were triggered by loose wet avalanches in motion.
Snowpack Summary
Rain has recently soaked the surface at all elevations. As freezing levels dropped on Monday, a new surface crust is expected to have formed. With lower freezing levels and ongoing precipitation, snowfall is expected to be burying the wet surface and/or surface crust.
Before the rainfall, new storm snow buried a highly variable old surface which included an unsupportive sun crust on southern aspects, spotty surface hoar in sheltered terrain, and heavily wind-affected surfaces in wind-exposed terrain.
A layer of decomposing surface hoar crystals could be found down 70 cm prior to the storm. There is also a layer of weak, sugary facet crystals near the base of the snowpack. During recent testing, both of these layers were producing hard results and there have been no recent reports of avalanches occurring on these layers. However, the current storm loading will test these layers and there still remains potential for avalanches in motion to step down to these older layers.
Overall, the snowpack continues to present as thin and averaged 130 cm deep at treeline prior to the storm.
Weather Summary
Monday night
Precipitation up to around 40 mm, strong to extreme SE-S wind, freezing level around 1200 m.
Tuesday
Precipitation 5-15 mm, strong S-SW wind, easing in the afternoon, freezing level reaching around 1700 m.
Wednesday
A mix of sun and cloud, moderate W wind, freezing level 800-1000 m.
Thursday
Precipitation 5-15 mm, moderate to strong S-SW wind, freezing level around 1000 m.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Give the new snow time to settle and stabilize before pushing into bigger terrain.
- Make observations and assess conditions continually as you travel.
- Be alert to conditions that change with aspect and elevation.
- Keep in mind that wet avalanches can be destructive due to their high density.
- A crust on the surface will help bind the snow together, but may make for tough travel conditions.
Problems
Storm Slabs
As freezing levels have dropped, the storm precipitation has likely switched from rain to snow at higher elevations. New slabs may be forming over a crust and/or the rain-soaked snow surface. Watch for signs of new slab formation, especially in wind-loaded terrain at higher elevations.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Loose Wet
Rain has likely soaked the snow surface at most elevations. Use extra caution on all steep slopes while it is raining or where the snow surface is wet.
Aspects: All aspects.
Elevations: Treeline, Below Treeline.
Likelihood
Expected Size
Valid until: Dec 27th, 2022 4:00PM
