Proto-Altaic: *si̯òmì ( ~ z-)
Meaning: wet snow, hoar-frost
Russian meaning: мокрый снег, иней
Comments: The match with Japanese is both phonetically and semantically precise, so the root seems quite reliable (despite sparse attestation in TM).
altet-prnum,altet-meaning,altet-rusmean,altet-mong,altet-tung,altet-jap,altet-reference,