Thunder Strike

Call for a thunder coming down on the target location. Each creature in 5 feet of the target location must make a Dexterity saving throw. A creature takes 8d8 thunder damage on a failed save and is stunned for 1 minute, or half as much damage on a successful one and it's not stunned.
The thunder ignites flammable objects in the area that aren't being worn or carried.

At Higher Levels. When you cast this spell using a spell slot of 4th level or higher, the damage increases by 1d8 for each slot level above 3rd.