Sunny skies forecast for Sunday. Strong solar radiation may result in increased avalanche activity. Storm slabs and persistent weak slabs may be easier to trigger with light loads.
Confidence
Moderate - Timing or intensity of solar radiation is uncertain
Weather Forecast
Clearing overnight with light westerly winds and freezing down to valley bottoms. Mostly clear with strong solar radiation on Sunday (chance of valley cloud) with cloud developing in the late afternoon. Light southwest winds and freezing levels climbing up to 1400 metres. Light snow starting overnight and continuing on Monday with moderate westerly winds and daytime freezing levels climbing from valley bottoms up to 1300 metres. Clear on Tuesday as the ridge re-develops, temperatures around -12 at treeline overnight.
Avalanche Summary
Wind loading followed by solar radiation resulted in a size 3.0 natural storm slab avalanche on a south aspect in the alpine on Friday. Another natural cornice fall size 2.0 was reported on Thursday from a north aspect in the alpine, it was also reported that this cornice did not release a storm slab on the slope below. On Wednesday a natural cornice fall resulted in a size 2.0 avalanche.
Snowpack Summary
The storm has ended and the sun is expected to bring strong solar radiation on Sunday. The storm resulted in about 40-60 cm over the past week. Below the storm snow you are likely to find a melt-freeze crust. This crust exists in most places except for higher elevation shaded terrain. In many areas there seems to be a reasonable bond between the crust and the overlying snow. I'd still keep an eye on this interface as it has become reactive on some features. Surface hoar buried in early January now lies up to 180cm below the surface and has become less of a concern. Possible triggers for this deep and destructive layer include a large cornice fall or significant warming from periods of strong solar radiation.
Problems
Storm Slabs
Storm Slab avalanches are the release of a cohesive layer (a slab) of new snow that breaks within new snow or on the old snow surface. Storm-slabs typically last between a few hours and few days (following snowfall). Storm-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.