frozen ground or permafrost


an accumulation or bank of snow formed when wind blows snow against an obstruction; often considerably thicker than the surrounding snowcover.

snow patch

relatively small area of snow cover remaining after the main snowmelt period.

snow cover

(1) in general, the accumulation of snow on the ground surface (2) the areal extent of snow-covered ground, usually expressed as percent of total area in a given region.

slope failure

mass movement of earth material down a slope; includes landslides, mudslides, debris flows, avalanches, etc; speed of movement can be sudden and catastrophic or slow.

single-phase thermosyphon

a passive heat transfer device, filled with either a liquid or a gas, installed to remove heat from the ground.

short-term strength

the failure strength of a material under a short-term loading (e.g. up to about 10 minutes in a uniaxial compression test).

shear strength

in geology, describes the compressive strength (ability to withstand pushing forces) of soils; results from two internal mechanisms: cohesion between soil particles, and friction caused by contact between particles; variable among different soils.

segregation potential

the ratio of the rate of moisture migration to the temperature gradient in a frozen soil near the 0 degrees Celsius isotherm.

segregated ice

ice in discrete layers or ice lenses, formed by ice segregation.

rock glacier

looks like a mountain glacier and has active flow; usually includes a poorly sorted mess of rocks and fine material; may include: (1) interstitial ice a meter or so below the surface (“ice-cemented”), (2) a buried core of ice (“ice-cored”), and/or (3) rock debris from avalanching snow and rock.

Frying Pan Glacier, Colorado, is almost entirely covered by rocks and debris in this photograph from 1966. (Photo courtesy of George L. Snyder, archived at the World Data Center for Glaciology, Boulder, CO.)


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