there are two chambers to it. the bottom one stays inflated to give you some guaranteed distance from the ground, and the top one deflates. once there's some snow/water on top of the thing, it's pretty slippery, so if you land awkward you usually slide it out anyway so it doesnt really hurt. granted, if you land straight on your dome, you're gonna be in sorry shape regardless of what you're landing on unless it's 3 feet of fresh snow.