Avalanche danger will increase if the the sun comes out and we get strong solar radiation combined with high freezing levels.
Confidence
Moderate - Timing or intensity of solar radiation is uncertain on Thursday
Weather Forecast
Overnight: Flurries or light snow with strong westerly winds and freezing at 1300 metres by morning. Thursday: Mix of sun and cloud with periods of strong solar radiation. Light winds with daytime freezing up to 1800 metres. Friday: Mostly sunny with light winds and daytime freezing up to at least 2300 metres. Saturday: Unsettled with flurries or light snow, not much of a re-freeze below 2000 metres. Westerly winds developing during the day.
Avalanche Summary
No new avalanches reported.
Snowpack Summary
A few more cm of new snow overnight, combined with gusty southwest winds has developed new wind slabs in the alpine and at treeline. Over the past several days we've had 10-30 cm of heavy snow at higher elevations, which sits on a thick hard crust that is quite solid above 1700m. 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, and may be triggered by large loads (eg: cornice fall) or warm temperatures (eg: full exposure to the sun).
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.
Loose Wet
Loose Wet avalanches are the release of wet unconsolidated snow or slush. These avalanches typically occur within layers of wet snow near the surface of the snowpack, but they may quickly gouge into lower snowpack layers. Like Loose Dry Avalanches, they start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-wet avalanches include point-release avalanches or sluffs. Loose Wet avalanches can trigger slab avalanches that break into deeper snow layers.
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.