Natural avalanches unlikely, human triggered possible.
Treeline
Natural avalanches unlikely, human triggered possible.
Below Treeline
Natural avalanches unlikely.
Alpine
Natural avalanches possible, human triggered probable.
Treeline
Natural avalanches unlikely, human triggered possible.
Below Treeline
Natural avalanches unlikely.
Alpine
Natural avalanches unlikely, human triggered possible.
Treeline
Natural avalanches unlikely, human triggered possible.
Below Treeline
Natural avalanches unlikely.
Regions
South Rockies.
Wind slabs may be easy to trigger where the wind has blown snow behind ridges.
Confidence
Fair - Intensity of incoming weather systems is uncertain
Weather Forecast
Tuesday is expected to be mostly dry, initially cold with freezing levels rising to around 1500 m in the afternoon. On Wednesday, a storm is expected to bring around 5-10 cm new snow during the day and a further 5-10 cm or so on Wednesday night. Freezing levels will rise to around 1700 m and ridgetop winds will peak at around 60 km/h from the southwest. On Thursday, lingering flurries should die out early in the day and freezing levels are expected to fall to valley bottom. Winds becomming light northeasterly.
Avalanche Summary
One size 2 natural avalanche was reported on Sunday. Additionally, explosive control produced a few size 1 and 2 wind slab avalanches, also on Sunday. If you have any avalanche observations to report, please send an email to [email protected].
Snowpack Summary
Generally light amounts of snow have fallen in the last few days. In the alpine, winds have been conducive to blowing this snow into thin wind slabs in exposed lee areas. Below the recent storm snow you may find a layer of surface hoar. Below this, about 20cm of settled snow overlies a thick hard supportive rain crust that extends from the valley to alpine elevations. The crust is effectively bridging triggers from penetrating to deeper persistent weaknesses that formed earlier in the season. However, on high alpine slopes above the recent rain line poorly bonded crusts, facets, and/or buried surface hoar may be susceptible to triggers. Professionals are still concerned with a buried crust from November, down 50-70 cm, that could be triggered by large loads.
Problems
Wind Slabs
Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.