Urban Noir Fantasy World

You can make the wall up to 60 feet long, 20 feet high, and 1 foot thick, or you can create a ringed wall up to 20 feet in diameter, 20 feet high, and 1 foot thick. The wall is opaque and lasts for the duration. Each creature in the area where the wall appears must make a Constitution saving throw. On a failed save, a creature takes 5d8 cold damage, or half as much damage on a successful one. A creature that ends its turn within 10 feet of the cold side of the wall takes 5d8 cold damage, and the ground in the area becomes difficult terrain due to ice.