You stand in the centre of a blizzard of your own making, wreaking havoc among your foes.

You summon a blizzard in a 500 foot radius around yourself. You may choose any sections in that area to not be affected by the blizzard. When you use this spell, after taking the action to initiate it, you may not take any other actions whatsoever during the three turns the blizzard is in existence.

Each creature in the blizzard must make a Constitution saving throw. Creatures that are flying have disadvantage on this save. Any creature that fails the save is knocked prone, takes 10d10 cold damage, and is incapacitated for the duration of the spell. Any creature that passes the save is not knocked prone, takes 5d10 cold damage, and its movement speed is reduced to 5.

At the beginning of the second round of the blizzard, all creatures must make another Constitution saving throw, with flying creatures suffering disadvantage. Any creature that fails this second constitution save, in addition to the first one, takes 10d10 cold damage, becomes unconscious, and you can move it in any direction up to 50 feet. Any creature that fails this constitution save, after passing the first constitution save, suffers the same effects as though it had just failed the first saving throw. Any creature that succeeds, in addition to succeeding the first save, takes 5d10 more cold damage.

At the beginning of the third round of the blizzard, all creatures must make a third Constitution saving throw, and flying creatures again have disadvantage on this. Any creature that fails after having failed the first two constitution saves takes 10d10 cold damage, then, if it is still alive, it becomes petrified, turning into an ice statue that cannot melt. Any creature fails after having failed one save and succeeded one save suffers the same effects as if had just failed the second save after failing the first save. Any creature that fails after succeeding the first two saves suffers the same effects as if it had just failed the first save.

During the round after the blizzard ends, creatures regain their original movement speed and all areas affected by the blizzard become difficult terrain for 1d4 days, due to massive amounts of snow on the ground. The following turn, all unconscious creatures will become conscious.

Any creatures caught in the blizzard that passed all of the Constitution saving throws gain vulnerability to fire damage for 1d4 hours. Those who failed one of the saving throws gain vulnerability to fire for 1d6 hours. Those who were affected by the blizzard and failed two or more saving throws gain vulnerability to fire for 2d4 hours.