Spring Conditions out there right now. We are expecting very high temperatures and clear skies tomorrow. Expect a widespread increase in avalanche hazard very quickly tomorrow.
Weather Forecast
Tonight the freezing level will fall to 1700m. There is also a weak inversion in the forecast for tonight and possibly tomorrow. Tomorrow will have a mix of sun and cloud and no precipitation. The alpine winds will be mostly light, but expect severe gusts up to 85km/hr. The freezing level will rise dramatically and top out at 3500m! A
Avalanche Summary
No direct observations today, however it is almost certain that there were loose wet avalanches in the later part of the day.
Snowpack Summary
Much of the snowpack is now isothermal by mid afternoon, meaning that it is mostly un supportive and extremely weak when not frozen. The recent weather pattern has encouraged a predictable freeze/thaw cycle making for crusty conditions in the morning and a weak, wet snowpack in the afternoon. Freezing levels extended to 2400m yesterday. Today's alpine high reached 10 degrees. Higher elevations that face true north still have a hint of a winter snowpack, although these places are getting to be fewer and fewer.
Problems
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.
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.