Two issues: snowpack structure and heating. The shallow snowpack structure is poor, which is why the danger ratings remain elevated. Sun and heat will increase the danger, usually in the afternoon when the crusts have melted, but with clouds rolling in on Friday this will become less of an issue.
Strong solar inputs could produce avalanches in steep rocky solar terrain. Pinwheeling and melting snow near rock are good indicators that the snowpack is being affected by solar radiation.
The lower snowpack consists of several weak layers that remain a concern. A combination of basal facets, and crusts are still possible to trigger. We are still seeing regular avalanches releasing on the deeper layers and snowpack tests are still giving moderate to hard sudden collapse results.
Our field team observed a 1-2 day old size 2.5 deep persistent slab on Dolomite peak today. Ski hills reported a warm day, but the snow surface remained mostly cool except on steep solar aspects. But, currently, it's 4 pm and the sun is high for a few more hours...
Surface crusts exist to ridgetop on solar aspects. On polar aspects, 10-25cm of storm snow sits over a facetted interface from March 25th and buried temperature crusts below 1500 m. The lower snowpack remains weak, with depth hoar producing sudden test failures in many locations.
The ridge of high pressure that has dominated the weather pattern this week is breaking down overnight and we can expect a change starting Friday. The weather switches to a SW flow, the wind will increase to 40 km/hr and a few flurries are expected and we might get 5 cm by Saturday. Freezing levels are forecasted to be about the same: 1500-2000 m.
