The snowpack will be under stress this weekend as temperatures increase. Remember, even small amounts of solar heating or rain can weaken snow quickly to cause an increase in the avalanche hazard beyond the posted danger ratings.
Weather Forecast
Continued precip through Friday with the freezing level dropping to about 1800m. Winds will pick up to strong. Clearing Friday night should allow for a light freeze but Saturday will bring sunny skies and a 3000m freezing level. A poor recovery is likely into Sunday with clouds and some light precip forecast. Conditions will be even warmer on Mon.
Snowpack Summary
10 to 20 cm of snow now lies on the April 11 crust that is found on N aspects to 2300m and to ridgelines on solar aspects. This is becoming soaked by rain as of late Thursday evening. The deeply buried February Facets and early season Basal Facets remain weak and will likely wake up with significant and sustained heating.
Avalanche Summary
Widespread Loose Wet activity is occurring as the falling rain soaks the fresh snow. These events have been up to size 1.5 running 10 to 15 cm deep over the April 11 crust on all aspects below about 2200m.
Confidence
Due to the number of field observations
Problems
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.
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.