Thalassic Calamity

Create a 400ft tall column of water in an 400ft radius centered on yourself. All living creatures in this area except for the caster and up to 5 chosen creatures, take 10d10 cold damage, or half as much on a CON save. you and your chosen creatures can breathe underwater and have a swim speed of 60ft while you concentrate on the spell. When you lose concentration, the column collapses and evaporates quickly.