The Winter Permit System is no longer in effect. We are into the spring pattern; with avalanche danger increasing on solar aspects through the day. Get an early start, watch for solar warming and avoid slopes threatened by cornices overhead.
Weather Forecast
Strong solar is expected today and Tuesday. Freezing levels are expected to rise to 1700m, with temps below treeline getting above freezing. Expect crusts to break down quickly. Cool alpine temps, -10'C, will help with overnight recoveries. On Wednesday, we should see increasing cloud as a system moves in, bringing precip and rising temps.
Snowpack Summary
Rain to 1900m turned to snow early Saturday. Above 1900m up to 20cm of snow overlies a variety of surfaces including crusts, surface hoar and moist isothermal snow. SW winds loaded lee slopes but have backed off overnight. The April 3rd crust is down around 50-60 cm. Snow below treeline is isothermal, but cool overnight temps are allowing recovery.
Avalanche Summary
Large avalanches continue to be reported. Size 2-2.5 solar triggered avalanches occurred yesterday from E and S aspects. A size 3, likely a day old, was observed on the NE face of Cougar. It propagated across most of the face, and likely failed on the March surface hoar. Last week skiers triggered a size 2.5 on N asp and size 3 on an NE aspect.
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.
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.
Persistent Slabs
Persistent Slab avalanches are the release of a cohesive layer of snow (a slab) in the middle to upper snowpack, when the bond to an underlying persistent weak layer breaks. Persistent layers include: surface hoar, depth hoar, near-surface facets, or faceted snow. Persistent weak layers can continue to produce avalanches for days, weeks or even months, making them especially dangerous and tricky. As additional snow and wind events build a thicker slab on top of the persistent weak layer, this avalanche problem may develop into a Deep Persistent Slab.