Avalanche Forecast
Regions: Banff, Banff Yoho Kootenay, East Side 93N, Field, Kootenay, LLSA, Lake Louise, Little Yoho, Sunshine, West Side 93N.
NW winds have gotten to much of the higher terrain, but soft snow still exists in sheltered areas. Be cautious if entering wind effected terrain and give the deep persistent problem some respect as we are still seeing triggering with light loads.
Confidence
Moderate
Avalanche Summary
A team in the Little Yoho area today saw little evidence of new avalanche activity on Tuesday
However, local ski hills were reporting continued natural and explosive triggered windslabs and deep persistent slabs
Notables included several slides to ground in the Lipalian area in the LL backcountry and a size 2 and 2.5 in NW and SE aspect alpine in the Delirium Dive area of the Sunshine backcountry. These failed on the basal facets with relatively small loads (2kg explosives)
Snowpack Summary
20-40 cm of recent snow has been blown by S/SW winds into windslabs in exposed alpine and treeline locations. In sheltered areas, non-wind effected snow sits on a layer of facets, suncrust and isolated surface hoar that was buried on Dec. 7th. Below this is a weak and facetted, early season midpack with two crust/facet layers near the bottom of the snowpack (Nov. 9th and Oct. 20th interfaces). Total snowpack depths at treeline are 60-100 cm.
Weather Summary
A ridge of high pressure sits over the area bringing cooler air and stable weather for a few days. Skies should be mostly clear with few clouds, moderate NW winds and high temperatures of ~ -5 to -10. We might see some light precip Wednesday overnight but nothing significant until the weekend.
Terrain and Travel Advice
- Be careful with wind-loaded pockets, especially near ridge crests and rollovers.
- If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.
Avalanche Problems
Wind Slabs
Moderate SW/W winds during the storm have created windslabs in lee features in the alpine and at treeline. These have been reactive to hand charges and ski cuts at local ski hills as well as several naturally triggered avalanches over the last few days.
Aspects: North, North East, East, South East, North West.
Elevations: Alpine, Treeline.
Likelihood: Possible - Likely
Expected Size: 1 - 2
Deep Persistent Slabs
Two weak layers near the base of the snowpack (Oct 20 and Nov 9) are producing slab avalanches down about 60-100 cm. Any surface windslabs have the potential to step down to this layer.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood: Possible - Likely
Expected Size: 1 - 2.5