Winter up high and spring down low leaves us with a highly variable snowpack and series of avalanche problems. Make continual assessments throughout the day as conditions can change rapidly.
Weather Forecast
Flurries dissipate today as a ridge of high pressure pushes in for tomorrow, than more unsettled weather on the weekend. Expect cloud, sun and flurries today with trace to a few cm of accumulation. The FL will rise to 1500m today, mod winds from the west and an alpine high of -4. Hoping for cooling temps tonight before the sun comes out tomorrow!
Snowpack Summary
Another 10cm of new snow adds to the incremental loading of late March, depositing 30cm in the last 2 days and over 60cm in the last week @ TL. Multiple crusts exist in the upper snowpack at TL and BTL, warming temps today will turn the surface moist this afternoon at lower elevations. Cornices keep growing in the alpine and should not be trusted!
Avalanche Summary
Artillery controlled avalanches in the Highway corridor up to size 3 yesterday, limited observations of natural avalanche activity due to poor visibility. No reports from skiers/riders in the back country, but there are fewer and fewer people out there as we transition into spring. On the 28th we observed a size 2 glide on a south asp btl.
Confidence
Due to the number and quality of field observations
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.
Loose Wet
Loose Wet avalanches are the release of wet unconsolidated snow or slush. These avalanches typically occur within layers of wet snow near the surface of the snowpack, but they may quickly gouge into lower snowpack layers. Like Loose Dry Avalanches, they start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-wet avalanches include point-release avalanches or sluffs. Loose Wet avalanches can trigger slab avalanches that break into deeper snow layers.
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.