The Snow Goose comes in two color morphs: a blue-gray body with a white head (blue morph) and an all white body and head (white morph). Most individuals of this species do not migrate through the mountains, but the occasional small flock makes almost annual appearances to local lakes outside of the park.
There are four park records to date, one of a dead white morph on the Little River Road just west of Park Headquarters from November 14, 1948 (Stupka 1963), one blue morph photographed in Cades Cove in late October, 1934 (ibid.), a large flock that spent parts of two days in Cades Cove at the end of November 1979, and a flock of ten birds, including at least one blue morph, that landed on the fields of Purchase Knob in mid-November, 2003, and stayed long enough for the attached picture to be taken.
References:
Stupka, A. 1963. Notes on the Birds of Great Smoky Mountains National Park. University of Tennessee Press, Knoxville.
Gough, G. A., Sauer, J. R., Iliff, M. Patuxent Bird Identification InfoCenter. 1998. Version 97.1. Patuxent Wildlife Research Center, Laurel, MD.