1. cascading pile of cellulite, usually located on the mid torso section of the body but in some rare occasions flabalanches have been reported in the jowl and thigh regions.
2. often associated with creatures that use the sir name jabba. see: jabba the slut
A: don't look now but your cousin is takin' off her shirt again.
A: that's got to be the biggest flabalanche i've ever seen! that's some seven layer burrito shit.
(noun): The abdominal area of someone whose body has normal fat distribution, except for their stomach, which is so fattened by beer, it is an avalanche of flab spilling over their pants.
Yo my uncle bob unbuttoned his pants and we gotsmothered in his flabalanche and nearly suffocated
The effect caused when a woman with a large gut or gunt wears low rise pants thus causing an avalanche of flab over the top of the pants. see also muffin top.