Alluvial Fan

Overview

Alluvial Fan is the park’s most dramatic lesson in how water reshapes mountains—a broad spill of truck‑size boulders with the Roaring River cascading through it. It’s a quick, family‑friendly stop that punches above its weight in scenery and story.

What You’ll See

• Horseshoe Falls pouring into a maze of granite boulders, with wide views across Endovalley and toward the Mummy Range.
• A paved/boardwalk path and a 56‑foot bridge linking the east and west sides, plus interpretive signs that make the place make sense.
• Plenty of rock‑hopping for the adventurous; many families let kids scramble on dry boulders close to the path.

Geology & History

On July 15, 1982, the Lawn Lake Dam failed and sent a torrent—over 200 million gallons—down the Roaring River, ripping out trees, rolling house‑sized rocks, and spreading them in a classic fan shape. Heavy rains in 2013 added fresh layers to the fan. Today the river threads through that debris, a living exhibit of flood power and landscape recovery.

Getting There & Layout

From the park’s Fall River side, follow Endovalley/Old Fall River Road to the signed East and West Alluvial Fan parking areas. The short path (roughly 0.6–0.7 miles round‑trip depending on where you start) leads to multiple waterfall lookouts. The west lot is the most straightforward for a gentle approach and has restrooms; the east approach includes a notably steep section right out of the gate.

Best Time to Visit

• Early morning or late afternoon for easier parking and softer light.
• Late spring/early summer snowmelt makes the cascades thunder.
• Fall brings glowing aspens in Endovalley.
• Winter can be icy; expect slick surfaces.

Timed‑entry reservations are required for this corridor during parts of the year—plan ahead.

Wildlife

Moose occasionally browse the streamside willows here, and elk are common in Endovalley. Give all wildlife plenty of space and never approach.

Safety & Etiquette

The river runs fast during snowmelt; wet rocks are slick. If you scramble, keep it on dry boulders, wear sturdy shoes, and keep kids within arm’s reach. Stay on signed paths and use the bridge to cross. There’s little shade—bring water and sun protection.

Make It a Mini‑Stop

This is an easy add between bigger hikes or scenic drives. Many visitors pair it with a leisurely cruise on Old Fall River Road for extra context on the valley.