zastrugi are Russian-language plurals; the singular is zastruga. The form sastruga started as the German-language transliteration of the Russian word заструга...

Greek taxis (arrangement)+nomia "distribution"[citation needed] Singular "sastruga", plural "sastrugi" (from Russian): new Latin-type singular "sastrugus"...

sastrugi (hard ridges on deep snow) is of Russian origin and its singular is sastruga; but the imagined Latin-type singular sastrugus has sometimes been used...