avalanche n.

"fall or slide of a mass of snow on a mountain slope," 1763, from French avalanche (17c.), from Romansch (Swiss) avalantze "descent," altered (by metathesis of -l- and -v-, probably influenced by Old French avaler "to descend, go down," avalage "descent, waterfall, avalanche") from Savoy dialect lavantse, from Provençal lavanca "avalanche," perhaps from a pre-Latin Alpine language (the suffix -anca suggests Ligurian). It was later extended to falls of rock and landslides. As a verb, from 1872.