(וַיָּבֵא יָדוֹ בְּחֵיקוֹ, וַיּוֹצִאָהּ, וְהִנֵּה יָדוֹ מְצֹרַעַת כַּשָּׁלֶג. (שְׁמוֹת ד:ו …and he (Moses) brought (placed) his hand in his bosom, and took it out, and behold his hand was leprous like snow. (Exodus 4:6)
To express that something is snowy, Hebrew plugs the rootשׁ.ל.ג (sh.l.g) into the passive-causative הֻפְעַל verb form, declaring that that object has been snowed. The passive verb becomes an adjective, and, voila, we get the word מֻשְׁלָג for snowy (מושלג is the masculine form). For example:
Visit Ktzat Ivrit.