Forecast snowfall and freezing levels are uncertain, but expect a pulse of weather on Tuesday night to drive up the danger on Wednesday.
Confidence
Moderate - Due to the number of field observations
Weather Forecast
TUESDAY NIGHT: A short pulse of warm wet weather overnight will bring 5-10 mm of precipitation, strong southwest wind, and freezing level up to 2000 m.WENDESDAY: Cloudy with isolated flurries, strong southwest wind, freezing level dropping to around 1800 m.THURSDAY: Mix of sun and cloud, moderate southwest wind, freezing level around 1700 m with alpine temperature around -4 C.FRIDAY: Increasing cloud, moderate southwest wind, alpine temperature around -1 C.
Avalanche Summary
No recent avalanches have been reported. Evidence of a large natural avalanche cycle during last week's storm has been reported around the Crowsnest Pass / Sparwood area (typically size 2.5 deep persistent slabs). A fresher size 3 avalanche in the Alexander Creek drainage was possibly triggered by a cornice fall on Sunday. Widespread natural activity in the neighboring Kananaskis region suggest conditions may be touchier north of Elkford.New snow should form wind slabs at higher elevations, well warming and cornice falls are potential triggers for deep persistent slab avalanches.
Snowpack Summary
Light amounts of alpine snow will form wind slabs in the alpine on Tuesday night. Meanwhile at lower elevations, light rain will soak the snowpack once again. Recent rain and sun have left a variety of crusts that are thicker and most supportive in open south facing terrain. Below the new snow and crusts, roughly 50-90 cm of snow sits above the February crust and facet interfaces. In some areas there may still be a poor bond to these interfaces. The bottom third of the snowpack is composed of weak facets and full-depth avalanches over this basal weakness remain a concern.
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.
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.