Mirages

Though popular lore has it that mirages occur in deserts, Fairbanks has an unusual number. It is quite common to look out across the Tanana Valley and see elevated lines of trees and rapidly changing square-topped images of the peaks in the Alaska Range to the south.

These mirages are caused by the layering that develops in the air when there is low atmospheric circulation in the valley. Light rays passing from the mountains to the viewer's eyes are frequently bent and trapped between the layers of differing optical characteristics.

Even when the air is stagnant, there is enough air movement to cause the mirage images to come and go rapidly. Unfortunately, the same layering that gives us glorious mirages compounds the severe air pollution problem in the Fairbanks area.