You unleash a flurry of extreme cold in a 30 ft. radius sphere centered on a point within range. Each creatures in that area, excluding the caster, must make a Constitution saving throw at disadvantage. On a failed save, a creature takes 5d10 cold damage and is petrified as ice freezes them solid. On a successful save, the creature takes half damage and is not petrified. While petrified in this way, the creature is immune to cold damage. Additionally, the ground in that area becomes difficult terrain for the duration of the spell.

If a creature moves into the affected space or starts its turn there, it must make the saving throw again.

For the duration, you can use your action to move the sphere up to 30 ft. If you maintain concentration for the entire duration, the sphere shatters and spreads. For 3 miles around the sphere, the area becomes extreme cold for 7 days unless magic of 9th level is used to reverse it.