Oil-canned belly, no damage to the blades, tailboom snapped off, gear was down but aircraft remained upright, floats inflated and still well attached to the fuselage. Since this is PPRUNE and not a court of law, I am free to speculate and don't have to wait for an official report.
My read is a high-speed vertical descent with little forward motion. Kind of what you'd get with a vortex-ring state. Aircraft hits water hard enough to oil-can the belly and snapping the tailboom off. Bug-eyed pilot has the collective up so high the coning of the blades keeps them from whacking the tail. Water sense switches activate the auto float inflation. If the floats had already been inflated before impact you'd likely see one or two torn up. Any forward speed and that turtle-lovin Puma wouldn't have remained upright.
Any passengers booking chiropractor visits?