Artic Ice Blast

a hail of rock hard ice pounds the ground in a 20foot radius 40 ft high cylinder  centered on a point within range. each creature in that area must make a constitution saving throw or take 3d6 bludgeoning  and 7d8 cold damage on a failed save, and ice stones turn's the area into difficult terrain until next turn. or half as much damage on a successful save.
when casting this spell at 7th level or higher the cold damage increases 1d8 cold damage for each slot above 6th