Heads up! Artillery fire is planned for the day. Due to recent construction, new artillery targets need to be sighted in. As always, check to make sure the area you want to ski / ride are open.
Weather Forecast
A stellar day to be in the alpine, mainly sunny skies with periods of clouds rolling through with a chance of isolated convective flurries throughout the day. Temps ranging from -11 to -19 with light ridgetop winds. Temps gradually warming and the first amount of significant snow will arrive over the weekend.
Snowpack Summary
Cold temps promoting facetting of the upper snowpack. Previous strong northerly winds have formed reverse loaded cornices. Windslab can be expected in the alpine and exposed areas well into treeline. On solar aspects, a crust is buried 40cm. Persistent weak layers from January and December are now buried 150-200cm.
Avalanche Summary
No new avalanches observed in the past two days. Skier controlled size 2.5 wind slab on Mt. Sifton and several skier controlled size 1.0 loose dry sluffs in the Hermit slide path several days ago. Several cornice failures earlier this week up to size 2.5.
Problems
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.
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.
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.