A warming trend is creating a dangerous slab above buried weak layers in some areas. Numerous persistent weak layers exist in the snowpack. Dry snow overlies two layers composed of weak and feathery surface hoar, with the deeper layer (December 15) buried 40 to 80 cm. This layer is found most often around and below treeline but has been reported as high as 2400 m. As the overlying dry snow becomes more cohesive and forms a slab, this layer has the potential to create easily-triggerable destructive slab avalanches. Where and when this will occur is tricky to predict and even professionals are scratching their heads about it. It is a good time for conservative decision-making.The snow surface is variable, consisting of dry snow on shaded aspects, a sun crust on steep solar aspects, and wind effect in exposed alpine and treeline locations.Deeper in the snowpack at depths of about 70 to 110 cm, a rain crust from November is producing variable snowpack test results, from sudden fracture characters to no result. This layer is considered dormant for now, but could be triggered where the snowpack is thin.Please share your recent observations through the
Mountain Information Network.