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drain channel

preferred path for meltwater to flow from the surface through a snow cover.

drift glacier

a semipermanent mass of firn formed by drifted snow behind obstructions or in the ground; also called a catchment glacier or a snowdrift glacier.

drift ice

ice that moves from winds, currents, or other forces.

drift of ice

displacement of a sea ice field from its place of origin under the effect of ocean currents and winds.

drifting buoy

floating (or drifting on ice) ocean buoy equipped with meteorological and/or oceanographic sensing instruments linked to transmitting equipment for sending the observed data to collecting centers.

drifting snow

snow raised from the surface of the earth by the wind to a height of less than 1.5 to 2.0 meters (5 to 6.6 feet) above the surface; it dose not restrict horizontal visibility at 2 meters (6.6 feet) or more above the surface.

drifting stations

research stations on the floes of the arctic ocean.


very small, uniformly distributed water drops that appear to float while following air currents; unlike fog droplets, drizzle falls to the ground.


remnant elongated hills formed by historical glacial action; it is not clear exactly how they are formed and why they form only in some glaciated regions.
Drumlin field. Manitoba, Canada.

drunken forest

trees leaning in random directions caused by melting permafrost.

dry density

the mass of a unit volume of dried material (e.g. soil).

dry frozen ground

frozen ground with a very low total water content consisting almost completely of interfacial water, and not cemented by ice.

dry permafrost

permafrost containing neither free water nor ice.

dump moraine

a mound or layer of moraine formed along the edge of a glacier by rock that falls off the ice; sometimes called a ground moraine.

dynamic modulus of elasticity

the ratio of stress to strain for a material under dynamic loading conditions.

dynamic Poisson's ratio

the absolute value of the ratio between the linear strain changes, perpendicular to and in the direction of a given uniaxial stress change, respectively, under dynamic loading conditions.