Avalanche Forecast
Regions: Little Yoho.
Winds have picked up in the alpine and fresh slabs should be expected Saturday as a cold front clears the region.
Give terrain with overhead hazard a miss until winds have backed off and continue to be cautious with solar slopes.
--more snow to come;)
Weather Forecast
Winds picked up Friday afternoon to Mod-Str W to SW as the warm front to a low passed just north of the forecast area. Up to 5cm of snow is expected overnight as the trailing cold front is set to pass over the region early Sat AM. Winds are expected to diminish following the passage of this front. Treeline temps will increase to reach -5C Saturday
Snowpack Summary
A new sun crust has formed over 5-10 cm of snow that sits over a sun crust on steep solar aspects. Winds on Wednesday developed reactive slabs in high alpine terrain and further slab development is ongoing Friday. February 16 sun crust down 30-40 cm on west, south and east aspects. January 30 facet or sun crust interface is down 50-80 cm.
Avalanche Summary
Tuesday a skier triggered a large persistent slab (size 3.5) on the SE slope of Vermillion Peak. Also Tuesday, we received a report of a cornice triggered size 2.5 slab on Mt. Carnarvon (YNP) - this one also likely ran on the crust. Groups on the Wapta for the week have reported several windslabs out as well as one large cornice failure.
Confidence
Intensity of incoming weather systems is uncertain on Saturday
Avalanche Problems
Wind Slabs
West winds have been building slabs in the high alpine since the middle of the week. Friday brought increased wind speeds and a shift in direction to the SW. Expect fresh slab development at the lower levels of the alpine / upper treeline Saturday.
Aspects: North, North East, East, South East, South.
Elevations: Alpine.
Likelihood: Possible - Likely
Expected Size: 1 - 2
Persistent Slabs
The crust/facet layer down 20-40cm on solar slopes at treeline and above produced a size 3.5 skier accidental avalanche on Mar 8. Give it a wide berth. Buried crusts are more prominent on solar aspects but temperature crusts exist on N slopes BTL too
- Dig down to find and test weak layers before committing to a line.
Aspects: South East, South, South West, West.
Elevations: All elevations.
Likelihood: Unlikely - Possible
Expected Size: 1.5 - 3