These are nice photo’s.Are you sure it is an ambulance? It seems to be a S.A.R helicopter as it has a winch.Anyway,what are “base jumpers”?

Yes you are probably right about it being an S.A.R. helicopter, my brother in law only thought it might be some kind of exercise with the Base Jumping. As has already ready been described what that is. Each to their own sport I suppose but it looks like madness to me.