Cryosphere glossary
mires
Also known as tundra mires, generally described as an area of wet, soggy, muddy ground., and often feature a layer of peat over permafrost.
mixed precipitation
precipitation consisting of a mixture of rain and wet snow; it usually occurs when the temperature of the air layer near the ground is slightly above freezing; the British term for this mixture is sleet (which has a different meaning in the United States).
moraine
a mound, ridge, or other distinct accumulation of glacial till.
Image
Lateral and terminal moraines of a valley glacier, Bylot Island, Canada. The glacier formed a massive sharp-crested lateral moraine at the maximum of its expansion during the Little Ice Age. The more rounded terminal moraine at the front consists of medial moraines that were created by the junction of tributary glaciers upstream.
Natural Resources Canada, copyright Terrain Sciences Division, Geological Survey of Canada
moraine shoal
glacial moraine that has formed a shallow place in water.
moulin
a nearly vertical channel in ice that is formed by flowing water; usually found after a relatively flat section of glacier in a region of transverse crevasses; also called a pothole.
mountain glacier
a glacier that is confined by surrounding mountain terrain; also called an alpine glacier.
Image
Taku Glacier winds through the mountains of southeastern Alaska, calving small icebergs into Taku Inlet. This photograph dates from 1929.
U. S. Navy, archived at the World Data Center for Glaciology, Boulder, CO
mountain permafrost
permafrost existing at high altitudes in high, middle, and low latitudes.
mountain wind
a cold wind blowing down an incline; a kind of katabatic wind.
mud circle
a type of nonsorted circle developed in fine-grained materials.
multiple retrogressive slide
a type of mass movement associated with shear failure in unfrozen sediments underlying permafrost, leading to detachment of blocks of frozen ground that move downslope.
multiyear ice
ice that has survived at least one melt season; it is typically 2 to 4 meters (6.6 to 13.1 feet) thick and thickens as more ice grows on its underside.
Image
Multiyear ice.
Ted Maksym, United States Naval Academy
n-factor
the ratio of the surface freezing or thawing index to the air freezing or thawing index.
needle ice
thin, elongated ice crystals that form perpendicular to the ground surface.
negative mill
a geyser; a fountain that develops when water from a conduit is forced up to the surface of a glacier.
net budget
the difference between accumulation and ablation; usually expressed in terms of volumes of water equivalent per unit area.
net terrestrial radiation
difference between the downward and upward terrestrial radiation fluxes; net flux of terrestrial radiation.
névé
(1) young, granular snow that has been partially melted, refrozen and compacted; névé that survives a full season is called firn; firn becomes glacial ice; (2) also refers to the accumulation zone of a glacier.
new ice
a general category of ice that consists of frazil, grease ice, slush, and shuga.
new snow
a recent snow deposit in which the original form of the ice crystals can be recognized.
niche glacier
very small glacier that occupies gullies and hollows on north-facing slopes (northern hemisphere); may develop into cirque glacier if conditions are favorable.