Intermittent Spring

Periodic Spring

Useful Information

Location: Near Afton, Wyoming.
Highway 89 to Afton, follow East 2nd Avenue which become Swift Creek Road/Higway 138 to the end. Park at Periodic Spring Parking. 1.3 km/15 minutes walk to the spring.
(42.745200, -110.849490)
Open: No restrictions.
Fee: Free.
Classification: KarstKarst Spring KarstIntermittent Spring
Light: n/a
Dimension: Y=2.800 l/s.
Guided tours: self guided
Photography: allowed
Accessibility: no
Address: Intermittent Spring, Afton, WY 83110.
As far as we know this information was accurate when it was published (see years in brackets), but may have changed since then.
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Intermittent Spring is an intermittent spring. No, that is not a joke, it is actually a lack of inspiration on the side of the guy who gave this spring its name. So it actually got a second name, which is Periodic Spring, because it's a periodic spring. It is said to be the largest rhythmic spring in the world. Fortunately they refrained from calling the spring Rhythmic Spring. Actually all three terms mean exactly the same, but were coined at different times by different authors. Among locals, it is also known as "the spring that breathes." Swift Creek Spring would have been probably a better name, as it is the source of Swift Creek, in the Swift Creek Canyon, a side valley of Star Valley near Afton, Wyoming.

The strange behaviour of the spring was discovered by chance by a woodcutter who came across the strange stream while working. He talked about it, and soon it became a natural attraction. The water from the spring flows continuously for 18 minutes before stopping for another 18 minutes, some say 15-20 minutes. There are only minor variations to this rhythm. The best time to visit the spring is late summer, when it is most active.

The site is quite well known and obviously frequented by tourists, nevertheless it is not a National Monument. If you want to see the spring you have to follow Swift Creek Drive to the end at Periodic Spring Parking, about 7 km on a single lane gravel road. From here it's a 1.2 km walk upstream on a well maintained trail to the spring. While there are no restrictions at all, the tour is weather depending, so we recommend the months MAY to SEP and to avoid storm and heavy rain. Good walking shoes, sun protection, raincoat, and some water and food are recommended.