Thunder River

 

By far the most popular of the North Rim's non-maintained trails, the Thunder River Trail takes you into an area with interesting geology, the world's shortest river, and aptly-named Thunder Spring, which roars out of a cave in the Redwall Limestone. You can do this as an overnight hike, but most backpackers like to take longer because of the long drive to the trailhead. There are plenty of side hikes that you can do from the Thunder River area.

Fall is the best season for a hike to Thunder River. Summer is too hot, and the access road is often impassable during the winter and spring.

Most hikers use the shorter Bill Hall Trail from Monument Point rather than the original trailhead from Indian Hollow. To reach the Bill Hall Trailhead from Jacob Lake on US 89A, drive south on AZ 67 0.4 miles, and then turn right onto Forest Road 461. Drive 5.2 miles, and then turn right onto FR 462. Continue 3.3 miles, and then turn left onto FR 422. Drive 11.4 miles, and then turn right onto FR 425. Drive 10.3 miles, and then bear right onto FR 292, which is the main road. Continue 2.9 miles as the road becomes FR 292A and ends at the Bill Hall Trailhead.

The Bill Hall Trail (named after a ranger who died in an accident) heads west along the rim to Monument Point, then descends steeply off the rim south of the point. It then heads north along the Toroweap Formation terraces to a break in the Coconino Sandstone, where it descends abruptly to the west to meet the Thunder River Trail on the broad terrace of the Esplanade. Turn left at this junction and follow the Thunder River Trail as the trail works it way south around drainages west of Bridgers Knoll. The trail then turns west and descends to a saddle. Turning south, the Thunder River Trail descends the Redwall Limestone in a series of short, steep switchbacks, finally coming out onto gentler terrain in Surprise Valley. Stay left at two junctions with the trails to Deer Creek.

Surprise Valley is the top of a huge slump block, where a massive section of Redwall Limestone slid down and tilted as it dropped. Across the valley, the summit of Cogswell Butte consists of layers of Supai Group rocks on top of the Redwall slump block.

Continue east on the Thunder River Trail, which climbs a bit to reach the east rim of Surprise Valley. Here you are suddenly greeted with the roar of Thunder Spring bursting out of its Redwall Limestone cave to form Thunder River. The trail continues a steep descent alongside Thunder River past small campsites, and ends where Thunder River meets Tapeats Creek.

You can explore cross-country upstream along Tapeats Creek, where you'll have to wade through a short narrows in the Tapeats Sandstone. A well-worn river-runner's trail leads down Tapeats Creek to the Colorado River. Another possible side hike starts at the junction with the Deer Creek Trail in Surprise Valley, and follows the Deer Creek Trail to Deer Valley.