Snow cornice Snow cornice A snow cornice or simply cornice (from the Italian cornice meaning "ledge") is an overhanging edge of snow on a ridge or the crest of a mountain and along the sides of gullies. They form by wind blowing snow over sharp terrain breaks (e.g. the crest of the mountain) where it attaches and builds out horizontally. This build-up is most common on the steeper and leeward sides of mountains. Cornices are extremely dangerous and travelling above or below them should be avoided. When a cornice "collapses", it breaks in from the cornice to the top of the peak;
Blue Ridge Mountain . Across the Potomac the ridge continues as Elk Ridge in Maryland. The mountain's ridgecrest forms the border between several counties, with Loudoun County and Fauquier County, both in Virginia, to the east and Jefferson County, West Virginia, Clarke County, Virginia, and Warren County, Virginia, to the west. Blue Ridge Mountain consists mostly of anticlinal Catoctin Greenstone and is not underlain by Old Rag Granite, as is the Blue Ridge south of Manassas Gap. This is why the mountain is more ridgelike and less rugged than sections to the south. The greenstone was deposited during the Catoctin Formation and uplifted