Dakari's icey radiance

You unleash a storm of freezing cold  and Devine energy in a 30 foot wide sphere centered on a point you can see within range. While in this area, creatures have the blinded condition, and they can’t cast spells with a Verbal component. 

When the storm appears, each creature in it makes a Constitution saving throw, taking 2d10 +10 Radiant damage and 4d10+10 Thunder damage on a failed save or half as much damage on a successful one. A creature also makes this save when it enters the spell’s area for the first time on a turn or ends its turn there. A creature makes this save only once per turn. for each save a creature makes they gain a level of exhaustion

Using a Higher-Level Spell Slot. The Radiant and cold damage increase by 1d10 for each spell slot level above 6.