Breath of the Boread 2.0

You expel the energy from within yourself to create a small blizzard of ice and snow that encircles a radius of 60ft around you, and persists until your concentration is broken. Any hostile target caught in it must make a Constitution saving throw. If the save fails, the target takes 1d6 of cold damage for each of their turns Breath of the Boread is active on. If the save is successful, the target's speed is halved for each of their turns Breath of the Boread is active on. The spell's damage die increase by 1d6 upon reaching 8th, 13th, and 19th level.