An ethereal waterfall created by a river of fog flowing over the cliffs of Látrabjarg, Iceland, a stunning example of katabatic wind; the downslope flow of cold, dense air under the force of gravity. Credit: Kjartan Gunnsteinsson

An ethereal waterfall created by a river of fog flowing over the cliffs of Látrabjarg, Iceland, a stunning example of katabatic wind; the downslope flow of cold, dense air under the force of gravity. Credit: Kjartan Gunnsteinsson