Jallarzi's Storm of Radiance

You unleash a storm of flashing light and raging thunder in a 10-foot-radius, 40-foot-high Cylinder centered on a point you can see within range. While in this area, creatures have the Blinded and Deafened conditions, 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 Radiant damage and 2d10 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.