Avalanche Forecast
Issued: Mar 4th, 2021 4:29PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs, Persistent Slabs and Loose Wet.
Lisa Paulson,
A Special Avalanche Warning is in effect, click here.
Beautiful day today! Expect another crust on solar aspects. Start and finish early, expect the hazard to increase as the day warms or with prolonged solar input.
Summary
Weather Forecast
A ridge of high pressure continues to bring mainly sunny skies, rising temperatures and 30-80km/hr winds from the South West. The freezing level is expected to rise again to ~2100m on Friday with valley bottom temperatures reaching +10. Expect increasing cloud Friday afternoon with light flurries overnight and into Saturday.
Snowpack Summary
Top 5 cm moist snow on steep solar aspects and top 5-10 cm at treeline and below (except North aspects). Previous strong SW winds scoured alpine ridges and created windslab in many exposed areas. These windslabs and two persistent layers of facets and sun crust down 30-80 cm are the sliding layers for avalanches to size 3 throughout the region.
Avalanche Summary
Wed/Thurs avalanche control produced impressive results up to size 3 involving the wind slab and/or persistent slabs, some running to the end of the runnout entraining weak snow in the track. A few natural slab avalanches to size 2 on E aspects and wet loose to size 1.5 on solar aspects.
Two close calls in the Simpson area of Kootenay last weekend.
Confidence
Problems
Wind Slabs
Sustained strong winds from the SW have blown the available snow into hard wind slabs in open areas. These can be quite deep in immediate lee areas and have been triggered by explosives and cornice failures.
- Use caution in lee areas. Recent wind loading has created slabs over weaker snow.
- Watch for shooting cracks or stiffer feeling snow. Avoid areas that appear wind loaded.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Persistent Slabs
Two weak facet interfaces exist in the top meter of the snowpack. They are the sliding layer for many recent explosive controlled, skier triggered, & natural avalanches. On south aspects this problem could be associated with a sun crust.
- Use conservative route selection, choose moderate angled and supported terrain with low consequence.
- Pay attention to overhead hazards like cornices which could easily trigger persistent slabs.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Loose Wet
Mostly clear skies and warm temperatures are forecasted again for Friday. The March sun is strong, and will pack a punch on solar aspects, weakening the upper snowpack. Steep, rocky terrain with thin snowpacks will be the most susceptible.
- Minimize exposure to steep, sun exposed slopes when the solar radiation is strong.
- Avoid ice climbs that are exposed to steep rocky terrain on solar aspects.
Aspects: South, South West, West.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Mar 5th, 2021 4:00PM
