Avalanche Forecast
Regions: South Rockies.
Confidence
Moderate - Due to the number and quality of field observations
Weather Forecast
TUESDAY: Scattered flurries with 5-10 cm of snow, strong southwest winds, freezing level around 2000 m.WEDNESDAY: Wet flurries with 5-10 cm of snow, strong southwest winds, freezing level around 2200 m.THURSDAY: Morning flurries then clearing in the afternoon with freezing levels dropping to 1500 m and strong southwest winds.
Avalanche Summary
On Sunday, several large cornice triggered slabs were reported in the southeast part of the region (up to size 2.5) and ski cutting produced a few size 1 slabs in the latest storm snow. On Thursday, explosive avalanche control along the White River (in the northwest corner of the region) produced over 10 deep persistent slab avalanches releasing on basal facets. Most of the avalanches were size 3, including several than ran full path to valley bottom taking out mature forest and blocking the river with up to 8 m of debris. While these avalanches were triggered with explosives, warm temperatures or solar radiation can have a similar impact on deep weak layers.Expect a range of avalanche problems during the next few days of warm weather. Touchy wind slabs will form at higher elevations, unstable wet snow may exist at lower elevations, and the possibility of large persistent slab avalanches will remain.
Snowpack Summary
A warm, wet, and windy storm will form fresh wind slabs at higher elevations while rain with fall below treeline. March has delivered regular storms with roughly 50-90 cm of snow sitting above crust and facet interfaces from February. In some areas the snow above these interfaces may have a poor bond. The mid-pack in this region is generally strong, but the bottom third of the snowpack is composed of weak sugary facets roughly 1-1.5 metres deep. This remains a concern and should be on your radar, especially with the recent loading and ongoing warming.
Avalanche Problems
Wind Slabs
Aspects: North, North East, East, South East, South.
Elevations: Alpine, Treeline.
Likelihood: Likely
Expected Size: 1 - 2
Deep Persistent Slabs
Aspects: All aspects.
Elevations: All elevations.
Likelihood: Possible
Expected Size: 2 - 3