Whelm

You tear open a rift into the elemental plane of water, unleashing a crushing vortex of water. Each creature in the vortex's space must make a Strength saving throw. On a failure, a target takes 4d6 bludgeoning damage. If it is Large or smaller, it is also [effect]grappled[/effect] (escape DC equals your spell save DC). Until this grapple ends, the target is [effect]restrained[/effect] and unable to breathe unless it can breathe water. If the saving throw is successful, the target is pushed out of the vortex's space.

 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.