"The spring the breathes" - The Periodic spring is the largest of three intermittent springs in the world. From late August to May, the flow cycles on and off at regular, predictable intervals. The spring runs up to 100 cubic feet per second of clear, ice cold water for about 18 minutes. The water then begins to subside and gradually ceases altogether for 15-20minutes. The Spring is located approximately five miles East of Afton, Wyoming.
Swift Creek cuts a narrow, deep limestone canyon into the Salt River Range, just outside of Afton, Wyoming. A gravel road winds up the lower canyon for about four miles. Trails leave this road at the North Fork of Swift Creek, where there is a foot bridge, and at the end of the road; the Swift Creek Trail traverses a steep slope north of the creek, and the Periodic Spring Trail travels along the creek side for about ½ mile to Periodic Spring, a natural cold-water geyser with a cascade racing down the talus to Swift Creek. Wildlife and birds can be seen in the canyon.