You whip up dust or sand into a raging sandstorm. Choose a point within range, and a 20-foot-radius, 20-foot-high cylinder of swirling dust or sand appears around it. The storm blocks line of sight for all creatures outside of it from seeing inside it, and vice versa.   A creature that starts its turn in the storm or enters the storm for the first time on a turn must make a Constitution saving throw. On a failure, a creature takes 6d6 bludgeoning damage and is blinded and has its speed halved until the end of its next turn. On a successful saving throw, it takes half as much damage and is not blinded.