"..Superior mirages Superior mirages occur in cold climates. In a superior mirage, surface ice cools the air as it reaches the surface. Upwards reflections are created when rays that are increasing in height get reflected downward through total internal reflection. Occaisionally, the combined iceberg/reflection looks like a large land mass. "Crocker Land", a mountain range that appeared on arctic maps from 1909 to 1916, was nothing more than a superior mirage. .."