Avalanche means like...an avalanche...you know...in those cartoons when the characters start a tiny snowball and as it goes down the mountain it becomes a big snowball. This is an avalanche:)
Avalanche is a bobsled ride. It is even designed to be like a bobsled: your legs are stretched out, and you can sit by your self or sit in someone's lap. This ride doesn't really have a drop, but many twists and turns that in the end, start going pretty fast (or so it seems). Avalanche is popular with the kiddies because many kids don't like tall hills, air time, or inversions, and Avalanche has none of these.