mass upon which the ice rests must be very great, and (2) the surface 



contours of the land must not be revealed on the upper surface of the ice. 



Cf. highland ice. See land ice. (Fig. 67.) 

 CORNICE: (II.B.) — Snow or ice overhanging an edge of a vertical cliff 



or a crevasse (Figs. 81, 82) . 

 CORRASION: (V.C.) — The wearing away of the surface of ice or other 



material through the friction of solid material transported by water or 



air. 

 CORRIE: (II.B.)— Cirque. 

 CRACK: (I.C.l.a.) — A small, unnavigable, narrow break in sea ice that 



may reveal the sea water surface. Cracks are usually caused by tides, 



temperature change, current, and/or wind. See water opening. 



(Figs. 30, 36, 62, 63.) 

 CREAM ICE: (I.A.3.)— Sludge. 

 CREVASSE: (II.B.) — A fissure or rift in glacier, shelf, or other land 



ice formations, due to temperature changes or motion of the ice. 



Crevasses may attain depths of 200 to 300 feet, but are commonly less. 



(Figs. 71, 72, 76, 78, 97.) 

 CUL DE SAC: (I.C.l.b.)— Blind lead. 

 CWM (pronounced koom) : (II.B.) — Cirque. 

 CWMICE: (II.A.l.d.)— Cirque ice. 

 DEBACLE: (IV.) — The breakup of ice in a stream or the rush of water 



or ice that follows. Cf. ice run. (Fig. 103.) 

 DEBRIS ICE: (V.C.) — Ice which contains mud, stones, shells, etc. 

 DEGLACIATION : (II.B.) — The uncovering of any area as a result of 



glacier shrinkage. 

 DE-ICING: (V.A.) — The prevention or removal of ice accumulation on 



ships. A measure to facilitate the removal of ice by weakening its 



adhesion is the application of a de-icing dressing by brush or spray gun. 



Removal devices include: Ice spike or pick, shovels, ice axe or mattock, 



steam hose, and a cradle-mounted jet engine. Cf. icing. 

 DENDRITIC GLACIER: (II.A.2.b.)— A mountain glacier having 



lateral tributaries. 

 DEPTH ICE: (I.B.l.d.)— Bottom ice. 

 DISTURBED ICE: (II.B.) — Any land ice which is broken by pressure 



into a chaotic pattern of elevations and depressions. Cf. pressure ice. 

 DOME-SHAPED ICEBERG: (II.A.5.a.)— An iceberg eroded in such 



a manner that its upper surface is well-rounded and smoothly contoured. 



This type iceberg is more common in the antarctic than the arctic. See 



iceberg. 



DONGA: (II.B.) — A small ravine, having steep sides, found in piedmont 

 ice or shelf ice. 



