Intermittent Spring (Wyoming)

An intermittent spring, also known as a periodic spring, is a spring that flows only sporadically or temporarily. Intermittent Spring in Wyoming, located near Afton, Wyoming, in Swift Creek Canyon within the Bridger-Teton National Forest, is one of the largest and most consistent examples of a cold-water intermittent spring in the world.

The spring's on-and-off flow pattern is due to a complex hydrological system involving underground caverns, siphons, and pressure dynamics. Water from snowmelt and rainfall infiltrates the porous limestone layers of the surrounding mountains and collects in a subterranean reservoir. As the reservoir fills, water levels eventually reach a point where they activate a natural siphon.

The siphon effect then rapidly drains the reservoir, causing a surge of water to gush from the spring's opening. This period of high flow typically lasts for several hours, often around 15-20 minutes on and 15-20 minutes off. After the reservoir is emptied, the flow stops until the reservoir refills, restarting the cycle. The exact timing of the on/off cycles can vary depending on factors such as the amount of recent precipitation and snowpack.

The unique geological conditions necessary for the formation of Intermittent Spring are relatively rare, making it a significant natural landmark. The spring is a popular tourist attraction, and interpretive signs are present to explain the hydrological processes at work. The surrounding area also supports diverse plant and animal life adapted to the fluctuating water levels. While other intermittent springs exist, the size, regularity, and ease of observation make Intermittent Spring in Wyoming a particularly notable example of this fascinating geological phenomenon. Its location within a protected national forest helps ensure its continued preservation.