Noun

1. A large mass or body of snow and ice sliding swiftly down a mountain side, or falling down a precipice.
2. A fall of earth, rocks, etc., similar to that of an avalanche of snow or ice.
3. A sudden, great, or irresistible descent or influx of anything.
4. Anything like an avalanche in suddenness and overwhelming quantity (like a barrage, blitz, etc).

Verb

1. To descend like an avalanche.
2. To come down upon; to overwhelm.

   The shelf broke and the boxes avalanched the workers.