Breath of the North Wind

Exhale a powerful discharge of radiant fire in a 15-foot cone. Each creature in that area must make a Dexterity saving throw, taking 6d6 radiant damage on a failed save, or half as much damage on a successful one.

At Higher Levels. When you cast this spell using a spell slot of 6th level or higher, the damage increases by 1d6 for each slot level above 5th.