Alluvial Fan

Alluvial Fan is a short riverside trail through a broad field of flood-deposited boulders, where the Roaring River breaks into cascades. Horseshoe Falls is the waterfall viewpoint at the upper end of the trail. The mix of rock field, river and falls makes this a worthwhile stop if you want to see the 1982 flood's work up close.

East and West parking areas serve opposite sides of the attraction. From the west, a rebuilt path climbs alongside the river to a 56-foot bridge over the Roaring River and connects to the east access. The rebuilt trail was designed for accessibility, though the access map marks slopes up to 19%; check whether that grade suits your group. The west lot has two single-user vault toilets, accessible spaces and picnic tables.

From the bridge, look along the boulder-lined river toward the Mummy Range and Endovalley. The upper viewpoint ends at Horseshoe Falls, framed by aspens; autumn color makes that view especially good for a photo.

On July 15, 1982, Lawn Lake Dam failed. The 26-foot earthfill irrigation dam had been built in 1903; its failure sent 674 acre-feet down the Roaring River, with a peak flow of 18,000 cubic feet per second. Three people died. USGS estimates that the flood deposited a 42.3-acre fan containing 10 million cubic feet of material. It also scoured the river channel as much as 50 feet and widened it by 300 feet. The boulders around you are part of that debris.

From the Fall River Entrance, take US 34 west and turn onto Endovalley Road for either lot. This is a heavily visited stop, so parking can be tight. The west lot is the one with restrooms and picnic tables.