Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
nĭvōsus, a, um, adj. [nix], full of snow, snowy: hiems gelida ac nivosa, Liv. 5, 13, 1: tantum nivosae grandinis, id. 21, 59, 8: Strymon, Ov. Tr. 5, 3, 22: Scythia, id. H. 12, 27: loca praegelida ac nivosa, Col. 2, 9, 7: Pliadum nivosum sidus, Stat. S. 1, 3, 95.