Tempting powder lines on North aspects today have the potential to fail as a slab avalanche. Test slopes before committing to your ski down. If the sun comes out this afternoon, be cautious if it starts to destabilize the snow surface.
Weather Forecast
A weak ridge of high pressure is expected to move into the interior today. Light precip this morning will give way to sun and cloud this afternoon. Freezing levels will rise to around 1800m with moderate southerly winds. Tomorrow freezing levels about 1600m with light precip. On Tuesday moderate snowfall with mod to strong winds is possible.
Snowpack Summary
20-30cm of HST overlies a crust. Deeper pockets of wind slab formed below ridge crests and on lee features from Southerly winds. Dry snow will be found on due N aspects and on other aspects above 1500m, this could change today with rising temperatures. Several crusts exist in the top meter of the snowpack. Isothermal snow developing on solar asp.
Avalanche Summary
Yesterday a cornice broke off a N aspect and triggered a size 2.0 slab avalanche which failed in the HST over a crust. Four other slides were observed, size 2.0-2.5. Most were loose moist, but one was a dry slab avalanche on a North asp. On due N aspects a field team was easily able to ski cut 10cm of HST over a crust which propagated as a slab.
Confidence
Intensity of incoming weather systems is uncertain on Tuesday
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.