Before we leave Christmas behind, let us take a look at the snowy Mt. Crumpit from How the Grinch Stole Christmas. Layouts are by Oscar Dufau and Don Morgan, and the backgrounds were painted by Phil De Guard, Bob Inman and Hal Ashmead.
Designer Maurice Noble, I suspect, is responsible for the mood colour change in that last frame, as the personality of the Grinch has turned bright and sunny. Colour-for-mood is employed elsewhere in the cartoon.