Avalanche Forecast
Regions: Little Yoho.
Conditions remain tricky now that is has warmed up following last week's storm. Many avalanches have occurred in both skiing and climbing terrain over the past week. Although we are over the peak of the cycle, give it more time to heal.
Weather Forecast
Another day of warm temperatures is expected on Wednesday, but this time with a bit more cloud cover and maybe a few flakes of snow. Expect treeline temperatures to reach 5 degrees, and the winds will return to SW 75-100 km/hr. The temperatures will begin to drop again on Thursday, accompanied by some more new snow (5 cm probably).
Snowpack Summary
45 cm of settled snow has formed a cohesive slab overlying a series of weak layers. Test results indicate "sudden" shear failures on these layers, which indicates that they are primed for triggering. Recent strong winds and warm temperatures have tipped the balance, and most slopes that have not avalanche should be considered highly suspect.
Avalanche Summary
Went to Sunshine Village today and was impressed by the widespread avalanche cycle that occurred the last 48-hours - many big, deep avalanches. Avalanche control on Tuesday produced an impressive size 3 avalanche on Vermillion Peak. Patrol up the Icefields Parkway today showed nothing new in the last 24-hr, but lots of large avalanches last 72-hr.
Confidence
Avalanche Problems
Wind Slabs
Strong to extreme winds from the SW have created wind slabs and fragile cornices that are ripe for triggering. Give avalanche terrain a wide berth and remember that fracture lines may extend further that you expect with hard slabs in alpine areas.
- Pay attention to overhead hazards like cornices which could easily trigger persistent slabs.
- If triggered the storm/wind slabs may step down to deeper layers resulting in large avalanches.
Aspects: North, North East, East, South East, South.
Elevations: Alpine, Treeline.
Likelihood: Likely
Expected Size: 1 - 3
Persistent Slabs
The recent snow has created a touchy slab over the weak facets at all elevations. Avalanches that have run full path have been observed in many areas.
- Avoid exposure to overhead avalanche terrain, large avalanches may reach the end of run out zones.
- Use conservative route selection, choose moderate angled and supported terrain with low consequence.
Aspects: All aspects.
Elevations: All elevations.
Likelihood: Possible - Likely
Expected Size: 2 - 3
Loose Wet
With temperatures climbing, all it will take is a brief period of clear skies and calm winds to have a major impact on steep slopes. Small solar or temperature triggered events are likely as the snow becomes moist.
- If triggered the loose wet sluffs may step down to deeper layers resulting in large avalanches.
- Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet.
Aspects: North, North East, East.
Elevations: Alpine.
Likelihood: Possible - Likely
Expected Size: 1 - 2