A series of inversions is on the forecast for the week end and early next week. How intense these will be remains to be seen. Keep an eye out for rising temperatures as you climb.
Weather Forecast
Tonight the wind will be from the west and average 20km/hr at 2500m The overnight low will be -13. Tomorrow will have a thin layer of cloud with sunny moments thrown in for good measure. The alpine temps will hopefully reach -12. Ridge winds will be from the west at 25km/hr. There is an inversion predicted for tomorrow, so be prepared for warmer temps in the alpine than the valley bottom. We're not sure how intense this inversion is going to be, watch for signs of warm air above. Melting snow on rocks and moist snow are all indicators of an inversion.
Avalanche Summary
Several loose dry avalanches (up to sz 1.5) were noted on N to S aspects today. A natural sz2 slab was noted on Mt Engadine. It was on a SW aspect, started in an alpine feature and entrained the facetted layers underneath. The suspected failure plain is a thin suncrust from the warm spell last week.
Snowpack Summary
After settlement, we were left with 8cm of new snow at most of our weather stations this morning. Some areas saw as little as 3cm. This snow has not seen any significant wind at any elevation. The only exception is near high alpine ridges where the local winds are amplified due to the terrain. Because of this, there may be localized storm slabs in immediate lee areas in the alpine. E & SE aspects are the aspects susceptible to this problem. Other than that, the storm snow has gained enough strength to keep the loose dry avalanches off the radar, atleast as long as the winds remain calm. Little change at treeline and below treeline. Windslabs are still in crossloaded terrain in the alpine. They are just barely buried under the new snow. Below treeline travel is still reasonable despite the cold temps last night. There is some surface faceting going on and we can expect that to become more pronounced as the cold nights persist.
Problems
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.
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.