The Coalpit Gulch route is by far the shortest approach for an ascent of North Thunder Mountain. Of course everything comes with a price, which in this case means an elevation gain of over 5,000 vertical feet in just 2.5 miles of hiking.
Steepness aside, this is a fun and challenging route to the summit of one of the most remote and seldomly visited Wasatch Front summits.
Alternate descent routes include dropping to the west from the summit into thunder bowl, or following the knife ridge ±0.9 miles south to the summit of South Thunder Mountain. Both of these options would involve a descent down Bells Canyon, which would of course require a shuttle vehicle.
The Entrance to Coalpit Gulch
The Coalpit Gulch route begins at the small powerplant a short distance up Little Cottonwood Canyon Road.
From the 6200 South exit (exit #6) off I-215 and follow highway 190 south-east approximately 2 miles to the intersection with Big Cottonwood Canyon road. Continue straight through the stoplight and follow the road another 4 miles to the mouth of Little Cottonwood Canyon, where an electronic billboard on the right provides current road and/or weather conditions.
From the electronic billboard drive 1.9 miles east up Little Cottonwood Canyon, to the small powerplant located next to the stream on the south side of the road. Park in the small parking area adjacent to the road directly to the west of the powerplant.
The Coalpit Gulch Headwall
One-Way Hiking Distance: 2.5 miles
Elevation Gain: 5,080 ft.
Average Gain per Mile: 2,032 ft.
Trailhead Elevation: 6,070 ft.
Summit Elevation: 11,150 ft.
Ascending the Northeast Ridge
From the parking area cross the bridge to the south side of the stream and turn left (east).
Follow the trail approximately 0.2 miles east, then begin looking for vague use trails on the right heading south. There are several of these faint trails, some of which will fade out after a short distance. Coalpit Gulch is the prominent notch in the wall of the canyon, approximately 0.2 miles south of the road. With a little luck you will end up on the main trail into the gulch, otherwise plan on some Class BW3 - BW4 bushwhacking as you routefind your way into the gulch.
Entering Coalpit Gulch the canyon walls quickly steepen on both sides; a number of bolted rock climbs line the wall on the east. A short distance after entering the gulch a small waterfall is bypassed on the left.
Continue up the drainage staying near the left (east) wall of the drainage. Roughly 100 yards above the first waterfall is a large overhanging boulder which effectively blocks progress along the left wall. Around the corner on the right is a second waterfall approximately 25 feet high; it may be possible to ascend the ledges to the right of the falls, but the rock near the falls is worn smooth and any spray from the waterfall will make the footing treacherous.
The preferred route through this section is a very steep slope dotted with several small pines, located roughly midway between the waterfall and the overhanging boulder. Climb directly up this slope through the trees, being very cautious as the dirt and rocks in this area are very loose.
Above this section the angle decreases briefly, and the stream moves to the far left side of the gulch. A short distance ahead is a third small waterfall, visible near the center of this photo.
This third waterfall is short (~10 feet) but involves tricky scrambling on loose (and very slippery if wet) rock. At the base of the falls climb up to a small ledge of broken rock on the right wall adjacent to the falls, then carefully traverse south back to the streambed above the falls. The most difficult scrambling of the route is now behind you.
Continue following the drainage as the gulch slowly begins to widen. At several locations the streambed will diverge into several smaller drainages; pick the ones which appear easiest to follow. Stay in or near the drainages as much as possible to avoid brush, but accept the fact that some bushwhacking will be required.
Higher up in the gulch a large boulder field is reached. Follow the boulder field upward, aiming for the lowest spot on the forested skyline directly south, until finally arriving in a large open cirque at an elevation of approximately 9,500 ft.
From this cirque will be the first clear view of the north face of North Thunder Mountain. On the left a grassy slope leads up to a saddle at the base of the north-east summit ridge. Ascend the slope up to the saddle, where an impressive view into Hogum Gulch to the east will open up.
From the saddle follow the northeast ridge as it climbs toward the summit. The ridge is steep and there is some exposure in spots, but careful routefinding will keep the scrambling to easy 3rd class. The high point on this ridge is a false summit, but the true summit is a fairly level and easy scramble about 100 yards to the south.
Entrance to Coalpit Gulch
Sturdy hiking boots with grippy soles.
The route involves a rather tricky climb around a short waterfall in the stream bed. A short (20-30 meter) rope for rappelling this spot on the downclimb is strongly recommended.