Avalanche Forecast
Issued: Mar 16th, 2021 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs, Loose Wet and Cornices.
swerner,
Avalanche Canada
Spring-like diurnal conditions exist and it allows travel in avalanche terrain to be favorable at this time. Pay attention to steep south facing slopes as they heat up in the afternoon and destabilize. Give looming cornices a wide berth from above and below.
Summary
Confidence
Moderate - Uncertainty is due to the limited number of field observations. Confidence is due to a stable weather pattern with little change expected.
Weather Forecast
A ridge of high pressure will remain anchored over the Interior until Thursday bringing warmer temperatures and sunny skies.Â
The typical spring-like diurnal weather pattern will hold afternoon alpine temperatures near -2 and freezing levels around 1500-2000 m. Overnight periods will see the freezing levels drop back to the valley bottom.
An approaching Pacific frontal system will move onto the coast Wednesday bringing unsettled weather and new snow to the Interior regions by Friday and through the weekend.Â
Avalanche Summary
No additional avalanche observations reported on Monday. I suspect daytime warming combined with solar radiation may pack enough punch to trigger loose wet avalanches, especially on sunny aspects. Large looming cornices may also become weak and fragile with warming.Â
Snowpack Summary
5-15 cm of recent new snow and moderate southwesterly winds have formed fresh wind slabs below alpine ridgetops. Dry snow can be found on north aspects and crusty snow surfaces exist on solar aspects. Large cornices loom over alpine ridges and become weak with afternoon warming.
A persistent weak layer made up of surface hoar at treeline elevations and a crust with facets in the alpine on solar aspects can be found down 50-150 cm in some parts of the region. Only one recent avalanche has been reported on a deeper layer and this involved a very heavy trigger (a cornice).
Terrain and Travel
- Watch for wind-loaded pockets especially around ridgecrest and in extreme terrain.
- A moist or wet snow surface, pinwheeling and natural avalanches are all indicators of a weakening snowpack.
- Back off slopes as the surface becomes moist or wet with rising temperatures.
- Pay attention to cornices and give them a wide berth when traveling on or below ridges.
Problems
Wind Slabs
Increasing winds on Wednesday may have formed wind slabs in isolated alpine locations. Steep, convex slopes below alpine ridgetops are the most likely places to trigger these slabs.
Aspects: North, North East, East.
Elevations: Alpine.
Likelihood
Expected Size
Loose Wet
Loose wet avalanches may occur during the heat of the day and primarily on solar aspects. Watch for changing snow surfaces while travelling like moist or wet snow, snowballing or natural avalanche activity. Steep slopes and around rocks will be most susceptible to natural avalanche activity.
Aspects: South East, South, South West.
Elevations: All elevations.
Likelihood
Expected Size
Cornices
Where cornices exist they pose a threat both from the potential for them to collapse under your feet (or machine) and from the potential to send large chunks of snow far down a slope. If anything can trigger the more stubborn persistent weak layers it's a large falling cornice. They are most likely to fail during the heat of the day.
Aspects: North, North East, East, South East.
Elevations: Alpine.
Likelihood
Expected Size
Valid until: Mar 17th, 2021 4:00PM
