Regions
South Coast Inland.
New snowfall likely won't bond well to underlying snow surfaces. Expect old and new slabs on all aspects at higher elevations, loose dry snow in sheltered areas, and looming cornices on ridgelines. Use caution on solar slopes when the sun is out.
Confidence
Moderate - Timing, track, or intensity of incoming weather system is uncertain
Weather Forecast
FRIDAY NIGHT: Cloudy with snowfall, accumulation 5 to 15 cm with the most in the south of the region, moderate to strong southwesterly winds, alpine temperature -13 C, freezing level below valley bottom.SATURDAY: Mostly sunny in the north of the region and cloudy with intermittent snowfall in the south of the region, accumulation 2 to 5 cm, light northwesterly winds, alpine temperature -12 C, freezing level near 500 m.SUNDAY: Cloudy with early-morning snowfall, accumulation 5 to 20 cm with the most in the south of the region, moderate to strong westerly winds, alpine temperature -7 C, freezing level near 700 m.MONDAY: Partly cloudy, light westerly winds, alpine temperature -10 C, freezing level 700 m.
Avalanche Summary
No new avalanche observations were noted on Wednesday or Thursday. On Tuesday, several natural loose dry avalanches up to size 1 were reported from steep south facing rocky terrain.Expect natural and human-triggered avalanche activity to increase with the incoming storms followed by warming sunshine.
Snowpack Summary
Around 10 to 20 cm of storm snow fell with strong westerly winds, producing storm slabs on all aspects with deeper deposits found in lee features. This snow fell on previously wind-affected surfaces. The new snow may not bond well to these surfaces and could be reactive to both natural and human triggers.In the snowpack in southern parts of the region, a widespread crust exists around 30 to 50 cm deep. Below the crust, well-consolidated snow exists.Avalanche professionals are still monitoring the mid-January crust and are avoiding shallow rocky slopes where triggering this layer is most likely. This layer is now 80-150 cm deep, but a heavy trigger (such as a cornice fall) or the next major storm (loading and/or warming) could wake this layer up.Also make note of cornices at ridgeline. Variable winds in the past month have produced cornices on all aspects. They will become touchier as they grow in size, as temperatures rise, and as the sun packs a strong punch on clear days. Stand well back of them and avoid them from below!
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.