AAA Editor Notes
Periodic Spring is about 5 mi. e. of Afton on FR 10211 (Swift Creek Rd.). In late summer the spring ceases to flow every 18 minutes, then gradually builds to a thundering, ice-cold torrent. This cycle occurs regularly for 9 months and fluctuates during the period of highest snow melt, from about mid-May to mid-August. A narrow dirt road leads to within half a mile of the spring; the last 200 yards of the hike are very steep.The road, not recommended for trailers, is closed during winter.Picnicking is permitted.