"Look, it is snowing!"
Translation:Titta, det snöar!
"Titta, snöar det!"? Is it okay or not? Sometimes I see they are flipping the word order and they call those sentences "bisatser". Can that rule be applied here?
Nope. A bisats (subordinate clause) is a sentence that "branches out" from the main sentence, or main clause. The sentence "Det snöar, när det snöar" (It snows when it snows) has two clauses, a main clause that makes sence on its own ("Det snöar"), and a subordinate clause that depends on information in the main clause ("... när det snöar").
Subject-verb reversal happens when you put the subordinate clause (bisats) before the main clause, unlike in English: "När det snöar, snöar det" (When it snows, it snows).
Outside of sentences with bisatser, subject-verb reversal is reserved for questions: "Titta, snöar det?" (Look, is it snowing?).