Avalanche Forecast
Issued: Feb 2nd, 2020 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs, Persistent Slabs and Deep Persistent Slabs.
mark herbison,
Parks Canada
Natural avalanche cycle up to size 3.5 throughout the region. Conservative decision making is essential.
Though triggering an avalanche below tree line is unlikely, avalanches from the alpine have been running full path, some reaching valley bottom.
Summary
Weather Forecast
Mainly sunny with a chance of isolated flurries on Monday. Temps ranging from -5 to -15 while the winds remain light from the West. Much of the same for Tuesday. Slight warming on Wednesday with 5-10cm of snow forecasted with increasing winds.
Snowpack Summary
30 to 70 cm of recent storm snow at higher elevations, with a rain crust up to 2000m. Wind slabs exist in the alpine and exposed areas at tree line. The Dec 31 layer of facets, surface hoar and sun crust is currently down 50-100cm. The deep persistent basal layer sits 20 to 40cm above the ground and is more developed in shallow snowpack areas.
Avalanche Summary
A widespread natural avalanche cycle occurred on Saturday up to sz 3.5, some of which gouged to ground. Explosive avalanche control throughout the region on Sunday produced results up to sz 3.5, the most notable being Mt. Field which heavily dusted the TCH while the powder cloud rolled up onto Mt. Stephan across the valley.
Confidence
Problems
Wind Slabs
Wind slabs developed rapidly along with fragile cornice growth from consistently strong Southwest winds. Despite the cooling trend, expect these slabs to remain sensitive to failure over the short term with continued natural activity.
- If triggered the wind slabs may step down to deeper layers resulting in large avalanches.
Aspects: North, North East, East, South East, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Persistent Slabs
This layer of surface hoar, facets and crusts is down 50 to 100cm and produces sudden pop/drop results in snowpack tests.
- Dig down to find and test weak layers before committing to a line.
Aspects: All aspects.
Elevations: Treeline.
Likelihood
Expected Size
Deep Persistent Slabs
With start zones loaded, avalanches can easily scrub to ground and entrain mass as they move through the track and into the run out zone. Many slides have reached valley bottom in the past 48 hrs.
- Avoid exposure to overhead avalanche terrain, large avalanches may reach the end of run out zones.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Feb 3rd, 2020 4:00PM
