That's Snow Ghost

The teenage sleuths search the witch's home then embark on an airboat pursuit only to unearth a wealth of greed and smoke screens. A ski trip to Wolfe's End Lodge becomes spooky with the appearance of a snow ghost. The sleuths follow the snow ghost's trail to a Tibetan temple where they learn of the threat of ghostly revenge, then to a nearby sawmill where Shaggy and Scooby take a toboggan ride that neither will soon forget.