The spell creates a 20-foot-radius sphere of mist similar to a fog cloud spell centered on a point you can see within range. The cloud spreads around corners, and the area it occupies is heavily obscured. A wind of moderate or greater velocity (at least 10 miles per hour) disperses it in 1 round. The fog is freezing cold; any creature that ends its turn in the area must make a Constitution saving throw. It takes 2d6 cold damage and gains one level of exhaustion on a failed save, or takes half as much damage and no exhaustion on a successful one.