These are the footprints of an ice pixie. They wear sneakers these days, but their footprints still grow up out of the snow like tulips. Actually this is the phenomenon of raised footprints — it happens in regions that experience weeks of cold, dry, windy weather, punctuated only by people with cameras.


Here we see a trail of footprints across Antarctica. Hopefully, for its maker, it is heading somewhere warm and secure, because by the time you see these footprints, there's nothing you can do for the person who made them, because they take weeks to form.

Raised footprints are the product of a very specific environment. The snow has to be loose and dry, so that the foot can sink in and compress the snow until it's hard. Since snowfall and rain can spoil the print, the weather has to be dry. And there has to be constant, miserable wind. As someone walks, their feet tamp down the snow until it's extremely hard in comparison to the snow all around it.


As the wind sweeps across the area, it whisks away loose particles of snow. It takes considerably longer to whisk away the compressed snow of the prints, so that sticks around. Eventually, the wind wears down an entire plain, or side of a hill, except for the hardened tracks in the snow. You can track someone by their prints weeks after they made them.

Images and Explanation: Alan R. Light