An over the top
pizza where the topping threatens to fall off in an avalanche, usually created at (drunken) make-your-own
pizza parties where the goal is to produce the gnarliest, most spectacular-looking
pizza.
Dude, check out this
pizza I made: it has
cheese, ham, mushrooms, chourico, tomato, garlic, pepperoni, salami, habanero peppers, artichoke,
chicken (whole), eisbein, peppadews, pineapple, more habanero peppers, and avocado. Oh yeah, and a duck.
Now that's what I call a pizzalanche.