noun

1. a mass of loosened snow, earth, rocks, etc. suddenly and swiftly sliding down a mountain, often growing as it descends
2. any large, overwhelming quantity that comes suddenly an avalanche of mail, of blows, etc.

Etymology: Fr (altered after avaler, to descend) < lavanche < Prov lavanca < *lavenca, prob. a pre-Roman word in a non-IE language of N Italy

intransitive verb, transitive verb avalanched -·lanched′, avalanching -·lanch′·ing