Choose a point you can see on the ground within range. Fissures open in the ground as lava and earth erupts in a 30-foot cube centered on that point. Each creature in that area must make a Dexterity saving throw. A creature takes 3d12 bludgeoning damage and 10d10 fire damage and is knocked prone on a failed save, or half as much damage on a successful one. 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.