In the early 1900s, cattleman brothers Julius and Amby Harper, who had a family ranch with their father in Rattlesnake Valley in the Cuyamacas, discovered a large, gently-sloping valley in the Pinyon Mountains while looking for areas suitable for winter grazing in the desert. In order to create a water source for their cattle, the brothers spent a few years constructing two concrete and rock dams in a narrow section of Pinyon Canyon at the valley’s west end. In addition, they built a one-room cabin in a small side canyon just downstream from the lower dam. These historic structures can be visited on foot by entering Harper Flat via Pinyon Wash from the north. A loop hike is described here, incorporating the cabin, dams, dry waterfalls, and a portion of Pinyon Mountain Road for the return loop.
From the parking area, begin the hike by scrambling up the boulders that block further vehicle access. Once past this initial obstacle, continue up Pinyon Wash as it alternates between mostly flat sandy sections interspersed with areas of minor rock scrambling. There are a variety of common desert plants found in this canyon that will burst into spring color given sufficient moisture. Chuparosa is covered with bright red tubular flows and is a favorite of several species of desert hummingbirds, whose long slender bills are well-suited for reaching the nectar hidden deep within the flower.
In the spring, look for the tall slender stalks of desert agave capped with masses of yellow blooms. This was an important food source for the Native Americans who inhabited this area. The long slender branches of ephedra, also known as desert tea, can be brewed into a mildly stimulating drink with effects similar to coffee.
Brittlebush will be covered in yellow sunflowers. Also called inciensio because the Spanish missionaries would collect its golden sap to be burned as incense. Resist the urge to touch the well-armed teddy bear cholla. Although it may look harmless and inviting from afar, it’s covered in spines and can detach in segments with the slightest touch. Often these “cholla balls” can be found on the ground surrounding the cactus, so watch your step so they don’t affix to your boots.
After about a mile, the canyon reaches the wide expanse of Harper Flat. Keep following the wide sandy wash as it continues south, hugging the western edge of the valley. In just over another mile, you will reach a fence that marks the state wilderness boundary. You are now on a dirt road that is open to 4WD vehicles entering from the west on the rough Pinyon Mountain Road.
Follow the road a short distance and then turn right (west) at the mouth of Pinyon Canyon. When this jeep road starts veering left, keep right to leave the road and enter the canyon. Pass an old water trough, and continue up a couple of dry waterfalls. After 0.4 mile from entering the canyon and just above a taller dry fall, turn left (south) up a small side drainage to find the remnants of the Harper cabin just around a bend in the wash. The metal and rock structure was built into the hillside and no longer has a roof, but inscriptions can still be found among the walls. Pause here and imagine what life might have been like in the harsh desert in the early 20th century, without all of our modern-day amenities.
Retrace your steps to the main canyon and continue up to find the lower dam, which can be climbed on the left by carefully finding strategic hand- and footholds. Once above the first dam, the second dam is in sight a short distance ahead. It is not as tall as the first and takes minimal effort to ascend. The two dams have long since filled with sand from when the Harper brothers constructed them in the early 1920s, after years of sediment runoff from further upstream.
Proceed up the canyon, choosing the best way up or around a few more dry waterfalls before coming upon the final challenge: a dry fall that is an intimidating 35 feet in height.
The sides of the canyon at this spot are too steep to allow a way to bypass the fall, so it must be climbed more or less straight up the middle. First, scramble to a narrow ledge partway up, then pick the best way possible for the remaining distance, keeping in mind that even though the rock may be dry, it is worn very smooth by years of water running over it, thus making it quite slippery. For extra assistance, a rope may be desired for this last section.
Once above this obstacle, the hard part is over. A short distance later, the Pinyon Mountain Road is reached, where you will turn left (south). Be cautious of vehicles that might be approaching, as you are now back on a route popular with off-roaders. After a few more ups and downs of the road, you’ll come across a stretch known as The Dropoff or Heart Attack Hill, a steep eroded descent with rocky bumps and ruts. If your timing is right, you may be witness to a few brave individuals maneuvering their rigs down this treacherous spot.
Continue on the road as it strikes a more easterly direction, and Harper Flat gets close once again. Veer left (north) when you reach the edge of the valley, and follow this back to the fence you crossed earlier, closing the loop portion of this hike. Re-enter the valley, once again skirting the western edge. If you have extra time to explore, look for a small rise to your right with some larger rocks on top. Many of these rocks contain morteros or slicks (grinding holes or depressions in rock) where Native Americans prepared food. You may find some ottery shards and obsidian flakings, but these must be left in place as per state and federal law.
Look to the northwest corner of the valley for your exit back down Pinyon Wash. The tall walls of the canyon will provide welcome shade from the sun on warmer days as you work your way down the remaining mile to the trailhead. Save a little energy for the last bouldery section at the end, taking care to descend safely.
Directions: (Tamarisk Grove Campground) From CA-78 turn south into the signed entrance of Pinyon Wash, 4.1 miles east of S-3 (Yaqui Pass Road) and 24 miles east of Julian. Go south 1.6 miles on the Pinyon Wash dirt road to the junction with Bighorn Canyon and Nolina Wash. Keep left, staying in Pinyon Wash. Go 3.3 miles to the end of the road and park, where there is room for several vehicles. No facilities. 4WD is recommended as Pinyon Wash may have areas of deep sand; call ABDSP Visitor Center for information on current road conditions.
Hiking length: 8-mile loop. Allow 6 hours hiking time.
Difficulty: Strenuous, with areas of boulder scrambling. Elevation gain/loss up to 1,300 feet.
Other: The best time of year to visit this area is November through April.