Polar Ice — The thickest and heaviest form of pack ice more than 

 1 year old. 



Polyhya — See Big Clearing. 



Pool — Polynya ; sometimes used to mean a depression on ice floes 

 filled with water as result of summer thaw. 



Pressure Ice — A general term for ice displaced vertically by pres- 

 sure resulting from action of wind, tide, temperature change, etc. 

 Rafted Ice — A type of pressure ice formed by one cake over-riding 

 another. 



Ram — A horizontal extension of floe or berg below its waterline. 

 Rotten Ice — Old ice in an advanced stage of disintegration as result 

 of melting. 



Sastrugi — Wavelike ridges of hard snow formed on a level surface 

 by the action of the wind with axes of the ridges at right angles 

 to the prevailing direction of the wind. 



Scattered Ice — Ice that covers less than one-half of the sea surface. 

 Sea Ice — A general term for all forms of ice encountered on the 

 surface of the sea. 

 Seracs — Ice pinnacles on a glacier. 



Shelf Ice — A thick, glacial ice formation extending from the land 

 but attached thereto. 



Shore Ice — Synonym of Fast or Coastal Ice. 

 Shore Lead — A lead between floating ice and the shore or between 

 floating ice and fast ice. 

 Sikussaq — Very old ice trapped in flords. 



Slush — A general term for an accumulation of ice crystals which 

 are either only slightly frozen together or separate. 

 Small Floe— See Floe. 



Snow Blink — Similar to ice blink except that glare created by light 

 reflected from snow-covered surfaces is white. 

 Storis — A regional term applied to large pieces of polar ice moving 

 along the coasts of Greenland from the Arctic Sea. 

 Sky Map — The mirroring of land, snow, or ice in the clouds. 

 Tracking — Following the edge of pack ice. 



Tundra — Stretch of mucky, treeless land covered with a variety of 

 hardy plants, including grasses, lichens, and shrubs. 

 Water Sky — Dark stretches or patches of grayness on the under- 

 side of extensive cloud areas due to the absence of reflected light 

 from open water areas. 

 Winter Ice — Sea-ice less than 1 year old. 



Young Ice — Newly formed ice in the transitional stage of develop- 

 ment from ice crust to winter ice. 



XII 



