Wind slabs remain reactive to human triggers. Pay attention to overhead hazards like cornices, especially when the sun is out.
Confidence
Moderate - Forecast snowfall amounts are uncertain on Friday
Weather Forecast
Thursday: Mostly sunny with treeline temperatures near -2 and freezing levels 500 m. Ridgetop winds light from the North.Friday: Overcast with new snow amounts 5-15 cm. Treeline temperatures near -2 and ridgetop winds strong from the South. Saturday: Mix of sun and cloud. Treeline temperatures near -2 with freezing levels 600 m. Light to moderate winds from the northwest.
Avalanche Summary
On Tuesday, several natural wind slab avalanches were reported from all aspects up to size 2. Although a couple of them were fresh, the bulk of them were up to 72 hours old. Natural avalanche activity is tapering, but human triggered slabs that sit above the buried crust remain possible.
Snowpack Summary
Surface snow is highly variable and wind-affected. In exposed terrain, strong north winds have scoured north facing slopes and loaded south facing slopes. In sheltered terrain, cold weather is preserving 30-50 cm of low density snow. A hard rain crust that extends into alpine terrain is buried about 40 cm beneath the recent storm snow. Reports suggest the snow has a poor bond to the crust with test results showing sudden planar characteristics and it remains reactive to human triggers. Monitor the bond of the snow to this crust closely. There are no significant layers of concern below the crust.
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.
Cornices
Cornice Fall is the release of an overhanging mass of snow that forms as the wind moves snow over a sharp terrain feature, such as a ridge, and deposits snow on the downwind (leeward) side. Cornices range in size from small wind drifts of soft snow to large overhangs of hard snow that are 30 feet (10 meters) or taller. They can break off the terrain suddenly and pull back onto the ridge top and catch people by surprise even on the flat ground above the slope. Even small cornices can have enough mass to be destructive and deadly. Cornice Fall can entrain loose surface snow or trigger slab avalanches.