Thunderous Crash

You raise your hands to the sky before bringing them down again as lightning streaks down around you. Creatures you can see within a 10ft wide cylinder around you must make a Dexterity saving throw (versus spellcaster's Spell Save DC). Creatures who fail the save take 1d8 lightning damage, and half as much on a successful save.

If a creature is wearing or wielding an item made of metal, they have disadvantage against the spell's Dexterity saving throw. 

When cast using higher level spell slots, the damage increases by an extra 1d8 per spell slot. e.g. 3d8 when cast using a 3rd level spell slot.