Blizzard

You conjure a burst of ice aspected aether around the target creature. The target must succeed on a Dexterity saving throw or it takes 1d8 cold damage and its speed is reduced by 5 feet until the start of your next turn. The target gains no benefit from cover for this saving throw.

At higher levels. The spell's damage increases by 1d8 and speed is reduced by an additional 5 feet when you reach 5th Level (2d8, speed reduced by 10 feet), 11th level (3d8 speed reduced by 15 feet), and 17th level (4d8 speed reduced by 20 feet).