|"Montana Mesas" - The Swan Range in northwest Montana as seen by Barbara Calm on January 18, 2009. ©Barbara Calm, shown with permission.
Montana has mountains but not towering mesas like these. Barbara was skiing at 6800 ft above a thick cloud layer and saw a superior mirage. The towering of some of the peaks even approaches a Fata Morgana mirage (1, 2).
The mirage was produced by strong temperature inversions, layers of abnormally cold air beneath warmer layers. A lower level inversion could also have been responsible for trapping the layer of cloud and fog in the valley beneath the camera.