word of warning. Be very careful digging tunnels. in 82 a friend of mine was nearly badly hurt when a snow tunnel collapsed on him. the panic as we frantically dug him out is still seared in my mind. he was OK, but it took us a while to get him out. we had to dig him out from the top down with our bare hands, and there were feet of snow on top of him. i don't know how old your son is. if he's big and strapping, he should be Ok, but if he's small, be careful