Fire Storm
A storm of fire appears within range. The area of the storm consists of up to ten 10-foot Cubes, which you arrange as you like. Each Cube must be contiguous with at least one other Cube. Each creature in the area makes a Dexterity saving throw, taking 7d10 Fire damage on a failed save or half as much damage on a successful one.
Flammable objects in the area that aren't being worn or carried start burning.
Fire Storm 5e 2024 vs. 2014 edition differences
The 2024 version clarifies that cubes must be contiguous, not just adjacent, and explicitly states flammable objects start burning, replacing "ignite" and "damage objects" language. Damage, range, duration, and area size remain the same.