Regions
Northwest Inland.
Avalanche danger will peak during the heat of the day.
Confidence
Fair - Freezing levels are uncertain
Weather Forecast
Expect generally fine weather through the forecast period. Light winds, warm daytime temperatures at alpine elevations and no precipitation.
Avalanche Summary
Large looming cornices are likely to start falling off with warm temperatures and solar radiation. Large slab avalanches that propagate across entire slopes are possible, especially with heavy triggers such as step-down avalanches, cliff-drops, and cornice drops.
Snowpack Summary
Total snowpack depths are well above average or even new record depths for this time of year. Weaknesses within the upper snowpack and the facets and surface hoar buried mid-January, create the potential for large step-down avalanches, but things seem to be settling rapidly.Snowpack tests on the mid-January facets down 80-150cm consistently produce sudden fractures and this weakness seems to be particularly touchy below 1500m where it is shallower and sits on a crust. Weak wind slabs and large fragile cornices are lurking in exposed lee and cross-loaded terrain.
Problems
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.
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.
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.