thanks for the explanation, I just wonder how people come up with the names for these maneuvers 'cos what you've just described looks nothing like avalanche to me. I'd rather call a waterfall avalanche.
ORIGINAL: BigNed
An avalanche is a loop with a snap roll at the top of the loop. You can do a positive snap (Up elevator and same rudder and aileron) but a negative snap(Down Elevator opposite rudder and aileron) helps keep the geometry of the loop better.