Does Flash allow you to cast a creature spell in response to a boardwipe?

Flash (CR 702.8) grants a permanent spell the ability to be cast any time you could cast an instant — including during an opponent's turn and, crucially, while another spell is on the stack. When a boardwipe (e.g., Wrath of God) is cast, it goes on the stack and players receive priority. You may use that priority window to cast your Flash creature before the wipe resolves.

The key timing rule is CR 116.1b: after each player casts a spell or activates an ability, all players get priority again in turn order. So once your opponent casts the boardwipe and you receive priority, you can cast your Flash creature in response. Both spells are now on the stack; the Flash creature resolves first (last-in, first-out per CR 608.1), entering the battlefield before the wipe resolves — and then the wipe will still destroy it.

This means casting the Flash creature in response usually does not save it from the wipe, because the wipe resolves afterward and will typically destroy the newly entered creature too. The value instead comes from getting any enters-the-battlefield (ETB) trigger or other immediate effect before the wipe resolves.

Concrete example: Your opponent casts Wrath of God. You respond by casting Briarbridge Tracker (which has Flash). The Tracker enters the battlefield, its ETB trigger goes on the stack and resolves (you create a Clue token). Then Wrath of God resolves, destroying the Tracker — but you keep the Clue token.

If your goal is to survive the boardwipe rather than just get an ETB, you would need the creature to also have indestructible, hexproof, or protection from the wipe's effect. Flash alone only controls when you cast; it does not grant protection from the boardwipe's resolution.