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"consolidated snow, the raw material of glaciers," 1853, literally "last year's snow, névé," from German Firn, from Swiss dialectal firn "of last year," from Middle High German virne "old," from Old High German firni, related to Old English fyrn "old," Gothic fairns "of last year," from Proto-Germanic *fur-/*for- (see first). The only English relic of a useful word meaning "of last year" that was widespread in Indo-European languages, cf. Lithuanian pernai "last year," Greek perysi "a year ago, last year," Sanskrit parut "of last year."
partially compacted granular snow that is the intermediate stage between snow and glacial ice. Firn is found under the snow that accumulates at the head of a glacier. It is formed under the pressure of overlying snow by the processes of compaction, recrystallization, localized melting, and the crushing of individual snowflakes. This process is thought to take a period of about one year. Annual layers of firn may often be detected by thin films of dust or ash that accumulate on the surface during each summer.