Ice A — The indicator group in the WMO Ice code 

 which denotes an aircraft ice observation. 



ice age — See glacial epoch. 



Ice B — Tlie indicator group in the WMO Ice code 

 which denotes a ship ice observation. 



ice bar — An ice edge consisting of ice floes com- 

 pacted by wind, sea, and swell, and difficult to 

 penetrate. (74) 



ice barrier — See ice shelf. 



ice-basin lake — A lake, pond, or pool on sea or 

 glacier ice. (59) 



ice bay — (also called ice Mght). 1. A bay-like 

 recess in the edge of a large ice floe or ice shelf. 



(5) 



2. An inward bend of the edge or limit of 

 pack ice, formed either by wind or current. 

 (65) 



ice belt — See belt. 



iceberg — (or berg). A large mass of detached 

 land ice floating in the sea or stranded in shallow 

 water. Irregular icebergs generally calve from 

 glaciers, whereas tabular icebergs and ice is- 

 lands are usually formed from shelf ice. Ice- 

 bergs are the largest form of floating glacier ice, 

 berg bits and growlers being generally the 

 fragments of broken icebergs. 



An iceberg is usually defined as being the size 

 of a ship or larger, although any piece of glacier 

 ice greater than 15 feet in height is often called 

 an iceberg. The TVHMO code defines an iceberg 

 as any piece of glacier ice more than 5 meters 

 (16.4 feet) above sea level. 



ice bight — See ice bay. 



ice blink — A relatively bright, usually yellowish- 

 white glare on the underside of a low cloud layer, 

 produced by light reflected from a distant ice- 

 covered surface such as pack ice. This term is 

 used in polar regions with reference to the sky 

 map ; ice blink is not as bright as snow blink, 

 but much brighter than water sky or land sky. 



ice boulder — A large fragment of sea ice stranded 

 on shore, which has been shaped by ice and wave 

 action into nearly spherical form. (59) 



icebound — Surrounded so closely by ice as to be 

 incapable of proceeding. If steering control is 

 lost, the ship is beset. If pressure is involved, 

 the ship is said to be nipped. ( 68 ) 



icebreaker — A ship specially designed for break- 

 ing channels through floating ice. (59) 



ice breccia — (or ice mosaic) . Ice pieces of differ- 

 ent age frozen together. (74) 



Ice C — The indicator group in the WMO Ice code 

 which denotes a shore ice observation. 



ice cake — (or cake, Mock). An ice floe smaller 

 than 10 meters (32.8 feet) across. (74) 



ice canopy — Pack ice and its enclosed water 

 areas from the point of view of the submariner. 



ice cap — A perennial cover of ice and snow over 

 an extensive portion of the earth's land surface. 

 The most important of the existing ice caps are 

 those on Antarctica and Greenland (the latter 

 often called inland ice) . (5) 



ice clearing — See polynya. 



ice cliff — See ice front. 



ice cluster — A concentration of sea ice covering 

 hundreds of square miles which is found in the 

 same region every summer. (7) 



ice crust — See ice rind. 



ice crystals — (or frazil crystals). 1. Fine spic- 

 ules or plates of ice suspended in water. (74) 

 2. See frazil ice. 



ice day — In climatology, a day on which the maxi- 

 mum air temperature in a thermometer shelter 

 does not rise above 32°F, and ice on the sur- 

 face of water does not thaw. 



This term is not used in the United States, 

 but is used in Great Britain, throughout most 

 of Eui'ope, and probably in many other parts of 

 the world. (5) 



ice edge — The boundary at any given time be- 

 tween the open sea and sea ice of any kind, 

 whether drifting or fast. (74) 



ice face — See ice front. 



ice fat — See grease ice. 



icefield — {ov field of ice) . 1. Any area of sea ice 

 of any size and of such extent that its limit 

 cannot be seen from the crow's nest. (74) 



2. An area of sea ice more than 5 n. miles 

 across; the largest areal subdivision of sea ice. 



ice floe — (or ftoe). A single piece of sea ice, 

 other than fast ice, large or small, described if 

 possible as "light" or "heavy" according to 

 thickness. 



Vast — over 10 kilometers (5.4 n. miles) across. 



Big— 1 to 10 kilometers (3,281 feet to 5.4 n. 

 miles) across. 



Medium— 200 to 1,000 meters (656 to 3,281 

 -pppf \ n, cross 



Small— lb to 200 meters (32.8 to 656 feet) 

 across. 

 (74) 



82 



