Intense solar radiation is expected to keep avalanche danger elevated tomorrow. Continued natural avalanche activity is possible.
Confidence
Moderate - Timing or intensity of solar radiation is uncertain
Weather Forecast
FRIDAY: Mainly sunny and dry with freezing levels back up to 2000m. Clouds are expected to roll back in early afternoon and winds should remain light to moderate southeasterly to southwesterly. SATURDAY Mainly cloudy with isolated light flurries possible, except east of the divide where it is expected to remain mostly clear. Freezing levels hovering around 2000m and moderate to strong southwesterly ridgetop winds. SUNDAY: Mainly sunny with cloudy periods, isolated light flurries possible with freezing levels dropping back down to 1700m and moderate to strong southwesterly ridgetop winds.
Avalanche Summary
Initial reports from Thursday include skier-controlled Size 1 fresh wind slab avalanches on the immediate leeward side of ridgecrests and terrain breaks. Natural wind and storm slab avalanche activity is expected on Thursday due to heavy loading from snow, wind and rain. On Friday, intense sun-exposure could trigger another round of natural activity, including cornice falls.
Snowpack Summary
10-15cm of fresh snow is bonding poorly to a widespread supportive crust. At higher elevations, touchy wind slabs linger below ridgecrests and behind terrain features in exposed terrain. Deeper in the snowpack, recent snowpack tests gave very easy sudden collapse results down 80cm on a southeast aspect at 1850m on the deep persistent facet/crust weakness from buried early December. Watch this weakness with extreme warming from sun-exposure, or warming/loading from rain. Cornices are also reported to be huge and weak.
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.