Elevation: 7,455 ft
This peak is not in the book. Published November 2018
Thunder Mountain is a small peak located south of Elba, ID, near ID-77. Its nearby neighbor to the northwest is Cache Peak (10,339 feet), the highest peak in the Albion Range. In the Grape Fire of September 2016, the east face of Cache Peak was completely scorched. But nearby Thunder Mountain was unaffected. This peak sees few visitors. I have no idea why this mountain is called “Thunder Mountain.” It certainly does not seem to be much of a lightning risk. USGS Elba
Northeast Shoulder, Class 2+
From the junction of ID-77 and Elba Road/1950 South in Elba, drive south on ID-77 for 6.2 miles to an unsigned dirt road on the right/west side of the highway. This is Grape Creek Road. The road has a large pullout near the highway and is initially on BLM land. Drive up this rocky desert road for 1.1 miles to the Sawtooth National Forest boundary at a cattle gate. There is no National Forest sign here, but there is a large “Entering Burn Area—Hazards Exist” sign just inside the cattle gate/fence. Park here (5,925 feet).
Hike up FSR-708 (unsigned) to the 6,200-foot level at the base of the northeast shoulder. Leave the road, cross a cattle fence, and descend 40 vertical feet to cross a small drainage (Grape Creek) to reach the toe of the northeast shoulder. Scramble west then southwest up the rounded, ill-defined shoulder. Near Grape Creek, there are some minor rock bands to scramble up over. The easy terrain is open and is mostly short scrub with a broken rock base for the first half of the ascent.
But higher up, the desert scrub thickens and mountain mahogany joins the mix. Initially, the mountain mahogany is scattered and can easily be maneuvered around. But by the time you reach 7,100 feet, the terrain gets rough. It becomes a mix of boulders and a dense forest of mountain mahogany. You will struggle to get through this stuff. The summit of Thunder Mountain is forested. The summit has a small cairn and a triangulation post laying in bushes nearby, tangled up in triangulation wires.
Northwest Ridge, Class 3
Same as for the northeast shoulder
This route is part of a ridge traverse from Thunder Mountain to Cache Peak. From the summit of Thunder Mountain, bushwhack west then northwest to descend to a 6,780-foot connecting saddle. This bushwhack is a BATTLE ROYALE. The terrain is a mix of thick mountain mahogany, boulders, and rocky outcrops/cliff bands. On top of that, the terrain is quite steep until you approach the saddle.
Lower down the ridge, the slope eases, cattle trails appear, and the terrain opens up. The final section of open desert scrub includes a cattle fence to the right/north and, the morning I was there, perplexed cattle on the other side of the fence. Follow the left/south side of the cattle fence to reach the gentle, small saddle.