Cataclysm

You strike the ground with your fist, letting loose a torrent of arcane fire in to the earth beneath you. Each creature within 30 feet of you must succeed on a Dexterity saving throw or take 5d8 fire damage, as well as 5d8 Bludgeoning damage, and be knocked prone. A creature that succeeds on its saving throw takes half as much damage and isn’t knocked prone. Additionally, the ground in that area becomes difficult terrain until cleared. Each 5-foot-square portion of the area requires at least 1 minute to clear by hand.

At Higher Levels. When you cast this spell using a spell slot of 5th level or higher, both damages increases by 1d8 for each slot level above 4th.

(A Tiz Spell).