Surface layers (windslabs in alpine lee areas, cornices and loose snow in sheltered areas) may become weak with solar radiation and forecast warming temperatures. A generally settled upper snowpack overlies two or more buried crusts. The December crust is found 70-140 cm below the surface and the November crust/facet layer is near the base of the snowpack. Recent snowpack tests have shown little reactivity on these layers, apart from in the Flathead Range near Fernie, where there is a lingering possibility of triggering a deep avalanche in specific thin, rocky snowpack areas. Check out the
forecaster’s blog for more discussion on this.