Natural avalanches unlikely, human triggered possible.
Alpine
Natural and human triggered avalanches likely.
Treeline
Natural avalanches possible, human triggered probable.
Below Treeline
Natural avalanches unlikely, human triggered possible.
Alpine
Natural avalanches possible, human triggered probable.
Treeline
Natural avalanches possible, human triggered probable.
Below Treeline
Natural avalanches unlikely, human triggered possible.
Regions
Banff Yoho Kootenay.
Large avalanches are occurring and there have been several close calls. Heed the advice and keep it mellow!Avalanche control on Mt. Bosworth, Field and Stephen in YNP, and Mt. Whymper and Vermillion in KNP on Monday. No outdoor activities please.
Weather Forecast
A mix of sun and cloud is forecast for Monday, with no snowfall expected. The cold temperatures will continues: expect lows of -21 and highs of -13 with winds from the north. Higher elevations may see some strong winds. No significant snowfall is forecast for the next few days.
Snowpack Summary
The 20 cm of storm snow from Thursday and Friday has tipped the balance and overloaded the weak, facetted snowpack. Windslabs have formed at higher elevations, and much snow remains available for wind transport in the days ahead. Although cold temperatures normally strengthen the snowpack, don't trust that theory now; the deep weakness prevails.
Avalanche Summary
A widespread avalanche cycle is occurring. We observed too many size 2's to mention, but size 2.5 or larger natural, explosive and human triggered avalanches in Corral Creek,Emerald Lake, Mt. Richardson, Numa Creek, Serac Creek and Floe Lake - we responded to two very close calls, and were amazed at the number of avalanches that occurred today.
Confidence
Problems
Deep Persistent Slabs
Deep Persistent Slab avalanches are the release of a thick cohesive layer of hard snow (a slab), when the bond breaks between the slab and an underlying persistent weak layer deep in the snowpack. The most common persistent weak layers involved in deep, persistent slabs are depth hoar or facets surrounding a deeply buried crust. Deep Persistent Slabs are typically hard to trigger, are very destructive and dangerous due to the large mass of snow involved, and can persist for months once developed. They are often triggered from areas where the snow is shallow and weak, and are particularly difficult to forecast for and manage.
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.