February 05, 2002
Rock ledges, scarps or any natural overhang may become draped with icefalls during the winter. The photo above shows a classic icefall near Cascade Lake in the Adirondack Mountains of New York. The process begins when the temperature is below freezing and a source of water is available so that frazil ice (a suspension of small ice crystals that can adhere to grass, soil or rock surfaces) forms as an anchor for the icefall. Much as the hanging dam at the eaves of a house roof provide the anchor for icicles, the frazil ice becomes the natural beginning of an icefall. Once the basic icefall forms, the details will be determined by the pathways of flowing water that freeze and add mass to the frozen falls. Many of the larger icefalls are well-suited for climbing.