Avoid exposure to large avalanche terrain during periods of active wind loading or significant warming. Cornice falls and wind slabs may act as triggers for deep persistent avalanches.
Weather Forecast
Tuesday: Sunny in the morning, with increasing afternoon cloud. Moderate to strong SW wind. Treeline temps, High -5, Low -7Wednesday: Mostly cloudy. Snow flurries (up to 10cm). Moderate to strong SW wind. Treeline temps, High -2, Low -5.Thursday: Mainly cloudy, flurries possible. Light to moderate SW wind. Treeline temps, High 0, Low -2
Snowpack Summary
Below treeline a supportive surface crust has been seeing a daily melt-freeze cycle. At treeline and in the alpine, wind exposed terrain is scoured and slick. Pockets of wind slab 5-30cm deep persist in sheltered lees, these will grow with snow and wind in the forecast. The bottom of the snowpack remains faceted and weak in many locations.
Avalanche Summary
No new avalanches have been observed. Several large to very large avalanches from last week and the week before suggest that deep persistent weaknesses in the snowpack will remain as a concern well in to the spring.
Confidence
Due to the number of field observations
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.