Cascading Frost

You produce a ripple of devastating cold at a point you can see in range. Every creature in a 15ft radius must succeed on a Constitution saving throw, taking 5d6 cold damage on a failure, or half as much on a success. Then you may choose to spread the ripple again, from any point within the first 15ft radius. All creatures within 15 feet of the second ripple make a Constitution saving throw, taking 2d6 cold damage on a failure or half as much on a success. If a target fails both saves, its speed is reduced by half until the end of its next turn.

At Higher Levels: The damage of both ripples increases by 1d6 for each slot level above 3rd.