Cryosphere glossary
Ice gland
A column of ice in the granular snow at the top of a glacier.
ice island
a form of tabular berg found in the Arctic Ocean, with a thickness of 30 - 50 meters (33 to 55 yards) and an area from a few thousand square meters to 500 square kilometers (123,550 acres); ice islands often have an undulating surface, which gives them a ribbed appearance from the air.
ice jam
an accumulation of broken river or sea ice caught in a narrow channel.
ice keel
from the point of view of the submariner, a downward-projecting ridge on the underside of the ice canopy; the counterpart of a ridge; ice keels may extend as much as 50 meters (55 yards) below sea level.
ice lens
a dominantly horizontal, lens-shaped body of ice of any dimension.
ice limit
the average position of the ice edge in any given month or period based on observations over a number of years.
ice patrol ship
a research ship which performs ice surveys in polar regions.
ice pellet
precipitation of small balls or pieces of ice (hailstones) with a diameter ranging from 5 to 50 millimeters (0.2 to 2.0 inches), or sometimes more, falling either separately or agglomerated into irregular lumps; when the diameter is less that about 5 millimeters (0.2 inch), the balls are called ice pellets.
ice piedmont
ice covering a costal strip of low-lying land backed by mountains; the surface of an ice piedmont slopes gently seawards and may be anything from 1 to 50 kilometers (0.6 to 31 miles) wide, fringing long stretches of coastline with ice cliffs; ice piedmonts frequently merge into ice shelves; a very narrow ice piedmont may be called an ice fringe.
ice prisms
a fall of unbranched ice crystals, in the form of needles, columns, or plates, often so tiny that they seem to be suspended in the air; these are visible mainly when they glitter in the sunshine (diamond dust); they may then produce a luminous pillar or other halo phenomena; this hydrometeor, which is frequent in polar regions, occurs at very low temperatures and in stable air masses.
ice quake
a shaking of ice caused by crevasse formation or jerky motion.
ice rind
a brittle, shiny crust of floating ice, formed on a quiet surface by direct freezing or from grease ice, usually in water of low salinity; thickness less than 5 centimeters (2 inches); easily broken by wind or swell, commonly breaking into rectangular pieces.
ice rise
a mass of ice resting on rock and surrounded either by an ice shelf, or partly by an ice shelf and partly by sea; no rock is exposed and there may be none above sea level; ice rises often have a dome-shaped surface; the largest known is about 100 kilometers (62 miles) across.
ice segregation
the formation of discrete layers or lenses of segregated ice in freezing mineral or organic soils, as a result of the migration (and subsequent freezing) of pore water.
ice sheet
a dome-shaped mass of glacier ice that covers surrounding terrain and is greater than 50,000 square kilometers (12 million acres) (e.g., the Greenland and Antarctic ice sheets).
ice shelf
portion of an ice sheet that spreads out over water.
ice skylight
from the point of view of the submariner, thin places in the ice canopy, usually less than 1 meter (3.3 feet) thick and appearing from below as relatively light, translucent patches in dark surroundings; the under-surface of an ice skylight is normally flat; ice skylights are called large if big enough for a submarine to attempt to surface through them (120 meters, 131 yards), or small if not.
ice stream
(1) a current of ice in an ice sheet or ice cap that flows faster than the surrounding ice (2) sometimes refers to the confluent sections of a branched-valley glacier (3) obsolete synonym of valley glaciers.
ice vein
an ice-filled crack or fissure in the ground.
ice wall
an ice cliff forming the seaward margin of an inland ice sheet, ice piedmont or ice rise; the rock basement may be at or below sea level.