A substantial storm is expected today, with high SW-NW winds and up to 25mm of precipitation. This will bump hazard up to HIGH tomorrow in the alpine, but be aware that it could get there later today.
Weather Forecast
A Pacific frontal system will bring moderate precipitation and strong winds to the area today. Winds will shift from SW to NW throughout the day, potentially resulting in reverse loading of snow onto south aspects. Expect thick cloud and mild temperatures. Tomorrow should be a nicer day, drier, maybe even some sun.
Snowpack Summary
Variable Conditions. In the alpine, SSL and HSL from last weeks storm and wind event overly crusts on solar aspects and facets or surface hoar on north aspects. The SH (from April 4) is best preserved above 2400m, and is reactive to skier triggering. Below treeline, the snowpack has become isothermal, frozen in the mornings, mush by afternoon.
Avalanche Summary
A few isolated avalanches were noted yesterday, and reports of "whumping" by skiers, mostly in the alpine. Glide cracks and cornices are growing larger, and are failing unpredictably. Three days ago, a size 3.0 natural slab avalanche in Youngs Peak Basin and a skier remotely triggered size 2.5 - 3 off of Youngs Peak Headwall.
Confidence
Timing, track, or intensity of incoming weather system is uncertain on Wednesday
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.
Deep Persistent Slabs
Deep Persistent Slab avalanches are the release of a thick cohesive layer of hard snow (a slab), when the bond breaks between the slab and an underlying persistent weak layer deep in the snowpack. The most common persistent weak layers involved in deep, persistent slabs are depth hoar or facets surrounding a deeply buried crust. Deep Persistent Slabs are typically hard to trigger, are very destructive and dangerous due to the large mass of snow involved, and can persist for months once developed. They are often triggered from areas where the snow is shallow and weak, and are particularly difficult to forecast for and manage.
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.