Dark Tornado

Cast forth a tornado of black winds around the target location in a 30-foot-radius sphere, targets are kept inside the tornado which obscures vision from the outside and inside, anyone who touches the winds will take 1d6 cold damage, if they wish to cross the wind barrier they must make a Strength Saving throw, on success they cross it and take another 1d6 of cold damage, on a fail they take 1d10 cold damage instead and are flung up 10 feet.