Avalanche

You conjure a powerful deluge of snow and ice on a point you can see within range. Every creature in a 20 foot cube centered on that point must make a Dexterity saving throw. On a failed save, a creature takes 4d10 cold and 4d10 bludgeoning damage and is knocked prone. On a successful save, the creature takes half damage and is not prone. At the end of each of your turns, including this one, the cube moves 20 feet away from you and both the cold and bludgeoning damage decrease by 1d10 (the movement direction of the area is set on your first turn; it continues moving the same direction even if you have moved on future turns). Any prone creature in the spell's area when it moves is moved with it. Any creature that starts its turn in the area or moves into it for the first time on its turn must immediately make the save. When the damage reaches 0, the spell ends and leaves a large puddle where it ended.