permafrost


per·ma·frost

noun \ˈpər-mə-ˌfrst\

: a layer of soil that is always frozen in very cold regions of the world

Full Definition of PERMAFROST

:  a permanently frozen layer at variable depth below the surface in frigid regions of a planet (as earth)

Origin of PERMAFROST

permanent + frost
First Known Use: 1943

Rhymes with PERMAFROST

permafrost

noun    (Concise Encyclopedia)

Perennially frozen earth, with a temperature below 32 °F (0 °C) continuously for two years or more. Permafrost is estimated to underlie 20% of the Earth's land surface and reaches depths of 5,000 ft (1,500 m) in northern Siberia. It occurs in 85% of Alaska, more than half of Russia and Canada, and probably all of Antarctica. Permafrost has a significant effect on plant and animal life, and it presents special problems in engineering projects. All land use in permafrost environments must take into account the terrain's special sensitivity; if the delicate natural balance is not maintained, extensive degradation and ecological damage may result.

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