On a surprisingly cool day in October, I decided to go back and hike a trail I had done years before. The trail was the Mt Umunhum Trail, and it’s definitely a gem!
Located just outside San Jose, Mt Umunhum is a prominent feature on the city’s skyline. Probably best known for the giant box on it’s summit (it’s an old radar installation), the summit can be seen from pretty much anywhere in the city! And when I say summit, I actually mean summit. At over 3,000 feet in elevation (3,489 to be exact), this is officially a mountain, making it one of the rare legit summits you can climb in the Bay!
Miles/Elevation:
7.7 miles
1,187 feet vertical gain
About Sierra Azul Open Space Preserve:
Always be sure to follow the 7 Leave No Trace Principles when in the outdoors!
Protecting 19,300 acres of natural landscape, Sierra Azul Open Space Preserve is a large area of protected landscape south of San Jose CA. Topped by the 3,400 foot plus Mt Umunhum, this area has some of the highest peaks in the Bay Area!
Sierra Azul has 26 miles of trails available for use for hikers, cyclists, and equestrians, and is located just minutes from San Jose itself, making it one of the best easily accessible outdoor areas in the South Bay!
Located on the inland side of the Santa Cruz Mountains, Sierra Azul does not have the Redwood forests of the coastal side, but is consistently wooded. Expect low, shrubby, trees, lots of bushes, and dry conditions! Temperatures get hot for much of the year, and shade isn’t always easy to come by!
Sierra Azul is great in and of itself, but it is also surrounded by other excellent parks and preserves! Almaden Quicksilver County Park, Calero County Park, Rancho Canada del Oro Open Space Preserve, and Lexington Reservoir County Park all ring Sierra Azul!
There is no fee to park in Sierra Azul Open Space Preserve.
Getting To The Trailhead:
The trailhead for Mt Umunhum is not far from San Jose, but it’s a bit of an adventure to get to. From pretty much anywhere in the Bay Area, you’ll need to get to highway 85 which wraps around the southern edge of San Jose.
From 85, it’s quickest to exit onto Camden Ave, head south, and eventually turn right onto Hicks Road. Hicks takes you into the woods, and is a windey 2 lane road. It’s a very pretty drive, Almaden Quicksilver Park is on your left, and Sierra Azul is on your right!
Eventually, you’ll reach an intersection with Mt Umunhum Road. You’ll need to turn onto Mt Umunhum Road here. The road goes all the way to the summit, but you’ll be driving up a mile or 2 to the Bald Mountain Parking Lot. Turn left into the lot, and you’re here!
Mt Umunhum Trail:
To Guadalupe Creek Overlook:
From the parking lot, the trail begins just across the street. Follow the crosswalk and you’ll easily see it. The entire way up to the summit is uphill, so don’t expect much for flat trail! None of the ascent is tough, it’s a very gentle sustained climb basically the whole way, but you have to maintain it for close to 4 miles!
Always follow basic trail etiquette when on trail!
The first quarter of a mile heads into the woods almost immediately after leaving the road. Follow the trail for a quarter of a mile, and then you will reach an intersection. Here you will intersect with Barlow Road, which can take you to the lower reaches of Sierra Azul. Do not go downhill here! You basically have to turn left, and then turn right immediately after. Don’t worry, if you just go left, you’ll hit the road, and don’t go downhill! Continue on the single track trail up the mountain!
Hiking in the Santa Cruz Mountains? Be sure to check out Castle Rock State Park!
After making it through that intersection, you’re pretty much done with the navigation on this hike. There’s a couple more turn offs that will take you to the road, but they’re pretty obvious to avoid. Basically just keep going up.
The trail on the first mile and a half is about 50/50 shade vs exposed. The climb is pretty gentle, but you’ll definitely be hot on the exposed sections, and you’ll probably still be warm in the shade!
Check out nearby Bear Creek Redwoods too!
The first real landmark on the hike is the Guadalupe Creek Overlook. It’s just under a mile and a half into the hike, and by this point you’ll have climbed about 350 vertical feet. The overlook is just a little ways down a side trail, and is worth seeing. The views aren’t much different from what you’ve been seeing already, but it’s a nice way to break up the walking!
To The Summit of Mt Umunhum:
From the overlook, you have about 2 miles to reach the parking lot just below the summit. Pretty much immediately after leaving the overlook, you’ll head into thicker forest. You’ll walk past the ruins of an abandoned cabin, and then the switchbacks start!
For more great views of San Jose, head to Monte Bello Open Space Reserve!
From the abandoned cabin, you have about 700 feet of ascending to do up a pretty serious set of switchbacks. The trail up to the parking lot is pretty well shaded, but it can still be warm. The trail through the switchbacks is well graded, smooth, and really not bad hiking at all! You should make pretty good progress, I even saw a lady hiking in a wedding dress through here!
Eventually, after the seemingly endless switchbacks which go on for what feels like forever even though the summit looks close the whole time, you’ll reach the summit parking lot. There is a trail that bypasses the parking area, but it’s been closed both times I have hiked this trail.
Almaden Quicksilver is really close and has more great hiking outside San Jose!
Unfortunately, even though you’re at the summit parking lot, you are definitely not there! You’ll probably see it, but there is about 100 feet of climbing straight up some brutal staircases! It feels cruel, but push through by far the steepest part of your day, and you’ll be on the summit!
The Summit:
The summit area is pretty built up and has a lot going on. There is a small parking/turnaround area for handicapped visitors. There is a large open circular area for gatherings, and lots of plaques and info boards around with tons of info on the wildlife and native history of the area.
The most conspicuous summit feature is the massive concrete block that towers over the parking area. Visible from basically all of San Jose, this giant block is the shell of a Cold War era radar installation. Obviously it’s no longer in use (it’s pretty easy to tell), but it’s an interesting feature to see up close!
Views from the summit
The Descent:
Enjoy your time on the summit, walk around and take in the 360 degree views, and when you’re ready, head back down the way you came. It would be pretty smart for one person to leave a car at the summit, and then drive back down to the lower parking lot, but it’s an easy hike back down.
The descent is on the same trail that you climbed up, and you should know by this point that it’s a gentle descent down. I actually enjoyed the descent quite a bit, so take it easy, and enjoy the fact that you just climbed a mountain!
Topdown Lifestyle Rating: 7/10
This is an enjoyable hike on a nice trail with good views. It’s always cool to actually summit a mountain, and this has to be one of the leading opportunities for that in the Bay Area. However, I can’t quite give this hike an 8.
Don’t get me wrong, I really like this trail, and I’ve done it multiple times. But, nothing quite stands out about it as great. The views are good, but there’s lots of nicer views nearby. The trail is nice, but there’s no exposed or exciting spots.
I really like this trail, and the distance, difficulty, and summit chance make it an enjoyable day on the trail, but it just isn’t quite spectacular enough to warrant an 8! Hike it if you get the chance though!
Pros:
- Very nice trail
- Summit opportunity
- Easily accessible
- Lots of good views
Cons:
- A lot of development
- No incredible views
- You can drive to the summit
Alternative Hikes:
Almaden Quicksilver County Park
Mount El Sombroso via Kennedy Trail
When To Visit Sierra Azul Open Space Preserve:
While you certainly could visit Sierra Azul in summer, it’s going to be hot. For me, I don’t love extreme heat, so I would probably try to avoid this area in the peak of summer, or if I did visit, I would be sure to go in the morning or the evening.
Sierra Azul is a great place to visit any time from fall through spring. Expect warm, pleasant temperatures in spring and fall and cooler days in winter, but in the sun it’ll probably still feel warm!
Sierra Azul benefits from the rain shadow created by the Santa Cruz Mountains, so it is quite dry throughout the year. Most rain will fall from December-March, but many days in that time will still likely be sunny. The dry does create fire risk later in the year, especially from August to November.
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