Zimba BM P900
Robison Mountain P1K
Rooster Comb

Sun, Apr 13, 2014
Story Photos / Slideshow Maps: 1 2 3 GPX Profile

Two days later I was back at the Dowdy Visitor Center of Henry Coe State Park. It was my 6th visit to the park this year, something of a record. Today I was on a quest to tag the remaining two prominence summits I had left in the range. There are 37 summits with more than 900ft of prominence and the last two were the most remote, located deep in the middle of the range. Robison Mtn is the highpoint of the Orestimba Wilderness while Zimba BM is found just outside the park to the east. Both were most easily reached from the Dowdy Entrance, though "most easily" is subjective - each is more than 15 miles one way. I had come to the park on previous occasions to find out the conditions of the main road I planned to bike. The first five miles proved exceptionally well-suited for bike travel on a good dirt road. Extrapolating from that, I figured I would be able to cycle the much longer distance in decent time. This was somewhat important because there are time limits at the Dowdy Entrance - the gate isn't opened until 8a on weekends and it closes again at sunset. Factoring in travel time of about 30min each way to the Visitor Center, that would leave me about 10.5hrs. As it turns out I had even less time than that because once I arrived at the Visitor Center I found that my back tire was completely flat, burning another half hour to remedy the situation.

I spent about an hour and a half biking north first on the well-graded Kaiser-Aetna Rd and then on the Orestimba Creek Rd which it becomes at a junction with County Line Rd. Orestimba Creek Rd is still pretty decent, but it crosses the creek a number of times. In times of high water this would make it virtually impassible, but at the moment it was only a minor inconvenience. I would stop at each crossing to carry the bike across - I'm a bit of a pansy when it comes to riding through creeks. The road eventually runs onto private property around the Gil Ranch, forcing bikes and pedestrians onto the Rooster Comb Trail that bypasses the creek and the ranch. This is a fine single track that climbs about 300ft above the creek as it winds its way around the east side of Rooster Comb before eventually dropping back down to join the road again north of Gil Ranch. I continued north on the road, once again back inside state property, for another mile, passing by a Jeep motoring up the road in the other direction. He looked a little surprised to see a bike out here as we passed each other with a friendly wave. It had taken about 2.5hrs to ride 15mi. This was my first inkling that my 30mi outing was going to be more like 40mi (in fact, 42mi before it was all said and done), a bit of weak planning on my part. But I was doing well on time and after finding a place to stash the bike away from the road, I started up to Zimba BM.

There's an old road coming up to Zimba from the northwest not shown on the topo map, but clearly visible in the satellite view. Reaching the start of this would have meant another mile north on the bike. Since the lower portions of the ridge are mostly grass, I short-cutted the road by starting up from the west side, climbing steep, but bushwhack-free slopes up from the Orestimba Creek drainage. I intersected the old road when I reached the ridgeline roughly near the park boundary marked by a fenceline. It was clear that grazing was allowed on one side of the fence, but not the other. Some interesting finds along the way were a deer antler, an old birdhouse and a horned lizard that are relatively common in the park compared to other places I've been in California. The old road follows SE up the ridgeline, nicely cutting through the swath of chaparral that covers much of the mountain's upper half. Bushwhacking through that stuff would have been much tougher. The road does not appear to have been driven on in years, but is still easily navigable on foot. At the boundary between the grass and brush I found a small herd of four horses grazing the slopes. Upon spotting me, they came walking up to greet me, hoping I would have something tasty for them to eat. Sadly, I did not. They even followed for a short distance as I continued up, but quickly gave up when they sensed there would be no goodwill coming their way. I crossed another property boundary partway up the hill. This upper ranch seems to be more active, probably for hunting purposes. There were some water troughs next to a motion-activated camera for monitoring game activity not far below the summit. A more active road could be seen a short distance to the east, though no one was to be seen out here today. I reached the summit around 12:20p finding a port-a-potty just to the south, overlooking a fine scene of the Diablo Range for more than 180 degrees. I was unable to locate the benchmark but I did find a reference mark near the highpoint on the ridge. To the west is the vast drainage of the Orestima with Robison Mtn rising high in the middle. To the north is Mt. Stakes, the highest summit in the area. To the east is the Central Valley to which the Orestimba drains. There is a gap between Wilcox Ridge and Black Mtn called the Orestima Narrows through which the creek flows. It is hard to get more remote than this in the Diablo Range, with the nearest pavement more than 10mi in any direction.

Returning to the bike by 1p via the same route, I went back to the Rooster Comb Trail in search of the route to Robison Mtn that I had somehow missed on the first pass. The Henry Coe Park map shows an old road labeled as the Robison Mountain Trail forking off the Rooster Comb Trail, but there were no signs at the junction. Luckily I had the route marked on the GPS so it was a simple matter to follow the trail back until the point indicated on the GPS. The only thing marking the junction was a small duck that is easy to miss. It's probably not a big deal to not find it - there appears to be other routes up from the south side that have only modest brush to contend with - but it's always nice to have an old roadbed to make things easier. This one hasn't seen a vehicle in decades. Robison Mtn is the centerpiece of the Orestimba Wilderness, the only wilderness found in the entire range. Not to say it's all that primitive. There are several other old roads through the wilderness and even a small manmade lake near Robison's summit, but it's a start. Leaving the bike, I followed what remains of the old road as it climbs steadily up the ridgeline heading northwest. There is a view to the Gil Ranch, below to the southeast as one climbs the ridge. Most of the mountain burned over in the 2007 Lick Fire, but as in most places where chaparral thrives, the stuff grows back quickly. Some of the oak and pine trees managed to survive and will slowly repopulate the more promising ravines and ridgetops if given a chance. The road was overgrown in several places, forcing me to find alternate routes to one side or the other, though none were what I would consider more than a minor inconvenience. It does appear that no one has done any maintenance on the route, perhaps not since the road was decommissioned decades ago. Though there was no register to help make it more educated, I'd venture a guess that the "trail" sees no more than a few parties on any given year.

It took a little over an hour to make my way from the bike to the summit which commands a decent view in 360 degrees, better than that on Zimba. Robison is surrounded by the Red, Robison and Orestimba Creeks, making it an island of sorts in the middle of the range without any connecting ridgelines to the other major ridges. There are no signs of civilization to be seen from the summit, just a sea of chaparral, oak woodlands and grassy slopes in all directions. Aside from the springtime greenery, there are a few colorful slopes of yellow poppies to be found on Robison. There are occasional flourishes of red or purple, but these tend to be smaller pockets and not very broadly distributed. I considered a visit to the nearby SNOD benchmark to the northwest, but the ridgeline to reach it appeared too brushy and I had to admit I was getting tired. Back down I went.

I returned to the bike by 3:20p and ten minutes later had reparked it at the trail junction for the Rooster Comb Summit Trail. It's the only other named summit in the area so it seemed a shame to pass it up, tired though I was. The trail was another old ranch road no longer used. It traverses up and across the north side of Rooster Comb, a rocky feature near the base of Robison Mtn. There is much poison oak found here and without the old road I would have turned back for sure. The road bypasses the summit, requiring some footwork backtracking to the east along the ridge, dodging poison oak, avoiding brush and even some rock scrambling. The summit block is an impressive chunk of rock that luckily has a class 3 route around the east side. Even this is tricky as some of the healthiest poison oak to be found is growing directly along this last scramble to the summit block. All in all, it was definitely a worthwhile side trip, the most interesting of the three summits.

It was almost 4:30p by the time I returned to the bike for the third time, all the summit objectives completed. It would take more than two hours to finish the ride back to Dowdy Ranch. My only break was near Pecheco Creek where I stopped to investigate a garter snake crossing the road. I picked it up for no better reason than snakes are fun to pick up, and afterwards set it back down and watched it slither off into the grass. I had worried a bit that I might be cutting it close in getting back to the Visitor Center. The gate at SR152 is scheduled to be closed at sunset which is about 7:30p this time of year. But I managed to get back by 6:30p, and with about 30min of driving to the gate, I had a small buffer of 30 additional minutes. After some 42 miles of hiking and biking, I was bushed. I even had to push the bike up portions of the last two miles of road out of Pacheco Creek that I had managed to ride previously. It had been a good day, though, reminding me just how big this park is. It would be my last visit to the Dowdy entrance for a while, but I would be back for a few more visits from the Park HQ entrance on the west side...

Kelly Johnson comments on 01/18/16:
Great report, the writing and photos. I especially liked the four photos in each direction from Mt. Zumba, especially the one looking East to central valley. I have seen those bare mountains from Mt. Wilson, and wondered if they were sort of the Eastern entrance from the Central Valley. I wonder if there is a road in from the East?
Anonymous comments on 09/08/16:
Bravo! I've never seen photos on the actual Rooster Comb. I've never been in that deep, but it's a beautiful park. Great trip report.
Submit online comments or corrections about the story.

More of Bob's Trip Reports

This page last updated: Thu Sep 8 21:42:38 2016
For corrections or comments, please send feedback to: snwbord@hotmail.com