The cascading flab that cliff-hangs over a belt buckle, or in particular, a pair of tight fitting hipster jeans. Most commonly seen on chubby pubescent girls.
"Will you just check out the fatalanche standing in the McDonald's line"
by Leha March 26, 2005
Alt Def: When the flesh rolls of a morbidly obese individual land on you while sitting at a sporting event, public performance, or on a plane, bus, or train.
Ex. Jack almost got buried in a fatalanche when a giant fat kid sat next to him at the Tiger’s game.
by zookpr April 16, 2009