There was next to no wind. Yesterday, 14 April, heightened avalanche activity was reported during the midday hours, generally loose-snow avalanches but also slab avalanches in the areas where snowfall was heaviest, and in all aspects. The necessary slab for a slab avalanche (a bonded snow mass above a weak layer) was generated by increasing warmth and diffuse radiation. In all likelihood the weak layer was comprised mostly of cold, loose-bonded powder snow. In the borderline foggy zones there may have also been surface hoar. We have recently observed the formation of faceted crystals near the surface (danger pattern: cold on warm) which may also have played a role (see last blog).
In a nutshell: due to increasing solar radiation and daytime warming, we can expect a highly active avalanche day today, particularly where recent snowfall has been heaviest. To an increasing extent, these will be loose-snow avalanches. Naturally triggered slab avalanches are still possible in high alpine regions, but in all likelihood today, 15 April, triggered by large additional loading, predominantly in very steep to extremely steep terrain.
