Wesson's Flash Freeze

As you throw a grenade to a point within range, it booms with a loud roar into an explosion of frost. Each creature in a 10-foot-radius sphere centered on that point must make a Dexterity saving throw. A target takes 3d8 cold damage on a failed save, or half as much damage on a successful one, If the area is in or on water, the radius becomes difficult terrain.

At Higher Levels. When you cast this spell using a spell slot of 3rd level or higher, the damage increases by 1d8 for each slot level above 3rd.