Mount Umunhum from Hicks Road

From Woods Trailhead Mount Umunhum is a 17 mile round trip with really great views all along the trail. The radar cube perched atop the summit, beckoning from the trailhead, grows in size until, in the final steps, it towers overhead. The vista from the summit fantastic.

Mount Umunhum is the most prominent peak in the Santa Cruz mountain range, notable for the large cube structure on its peak. During the second world war the peak was an army base and the cube is the base of a radar dish installation that scanned the Pacific coast. Last September the newly constructed trial and rehabilitated peak was opened to the public, and I’ve been looking forward to visiting ever since.

Mount Umunhum is visible from Woods Trailhead, 8 trail miles away.

The road actually goes right up to just shy of the peak, and there’s another trailhead 3½ miles from the top, from which the new Mount Umunhum Trail begins, at Bald Mountain, but I wanted a more challenging hike so I started at Hicks Road from Woods Trailhead. From here the peak is a little over 8 miles away with a little over 3,000 feet of climbing.

The morning sun looking back along Woods Trail.

Mount Umunhum Road is closed from half and hour after sunset until sunrise (actually, as I would discover, 7am). At the entrance there’s an automated gate, and the Woods Trailhead is just on the other side, so you can’t park up earlier. I arrived 10 minutes before the gate opened and set off for the morning shortly after the gate automatically rose at exactly 7, setting off in the cool morning air, the sun already starting to beat down.

Woods Trail is a continuation of the dirt road the reaches across the Sierra Azul Open Space Preserve to Kennedy Trail and Lexington Reservoir, following the power lines. As it contours around the steep-sided valleys fantastic views across the open space and beyond to San José and the mountains on the far side are frequently visible. This section is actually reasonably flat, at first a descent to cross Guadalupe Creek, and then climbing back up to meet Barlow Road.

Power lines stretch across the slopes of Sierra Azul and beyond through Almaden Quicksilver County Park beyond.

Barlow Road starts off steep and carries on that way for little while. This is definitely the steepest part of the hike. The trail first climbs up and over a ridgeline before dropping back down to again crossover Guadalupe Creek. At this time of year the creek is still flowing, not very fast, but enough to cool the air in the gully. The climbing resumes, and Barlow Road ends at the junction with the newly constructed trail to Mount Umunhum.

Trees arching and wrapping around Mount Umunhum Trail

Up to this point I haven’t seen anyone else on the trail all morning, I can’t imagine many people hike down Barlow Road, although it does have some great views out and across the valley, but clearly the main attraction is Mount Umunhum itself. This changed quickly on the Umunhum Trail, popular with hikers, and deservedly so. Unlike the rest of the trail system in Sierra Azul, which is just old dirt roads that have been handed over to hikers, the trail to Mount Umunhum is the longest newly built trail in the Midpeninsula Regional Open Space system, graded for people rather than trucks.

Bridge over Guadalupe Creek on Mount Umunhum Trail. The flow was nothing more than a trickle at this point, but the creek was covered in moss.

The Umunhum Trail climbs gently, but persistently, through the rich and varied flora, the grasses still wet from morning dew. A mile up the trail a short detour leads to Guadalupe Overlook which has a great view out across the steep-sided valley and over to the valley below. Just up from the overlook the trail crosses over Guadalupe Creek a couple more times as it switchbacks up towards the summit.

On the final ascent the cube, visible since the very start, is starting to loom, standing on top of jagged rock outcropping. Shortly before the top the trail splits to loop around to the summit from the east or to join the road and approach from the west.

Woods Trail meandering up to Mount El Sombroso, San Jose and the San Francisco Bay off in the distance.

On the day of my hike however the east approach and the area immediately around the cube is closed. When the peak was reopened it involved a lot of cleanup of hazardous materials from the old army base, which was a big part of the cost and duration of the project. The cube, always white, was repainted to seal in the asbestos and lead paint covering it. However, when it rained in the winter the paint started to run, exposing the contaminants below, so its being worked on again to clean it up. In all my photos the cube has had the paint stripped revealing the raw concrete below, it’s much more prominent in its usual white.

The radar tower at the summit of Mount Umunhum. It’s usually painted white but as it’s being cleaned of contaminants it’s currently stripped and the concrete below is visible.

Between the parking lot near the summit the top is 159 concrete steps, so perhaps I should take it back, this is the steepest section. At the top the summit itself has been restored to a rock garden and “ceremonial circle”, but the real treat are the views, which are fantastic. The 3 other peaks surrounding the bay area are all visible; Mount Tam, Mount Diablo, and Mount Hamilton, as well as the steep valleys and vast valley below.

Because of the car access the summit it thronging with people, so after spending a short period taking in the view I turn around and head back down. On the way down I see more people coming up Barlow Road and Woods Trail, although now later in the day it’s much hotter and less pleasant. In the late spring the early morning is definitely the best time to start this hike, I’m already back at home and resting before the more intense heat of late afternoon hits.

Kennedy Trail at Sierra Azul

A great trail for views across south Silicon Valley and hill climbing, although be warned it’s scorching hot in the summer, early mornings are best.

Sierra Azul Open Space Preserve is a rugged and steep park on the edge of Santa Cruz mountains. The trail system is mostly old fire roads which were not designed for hikers and are persistently steep, but partly it comes with the terrain.

The trail system is actually pretty extensive, especially now that the trail to Mount Umunhum has opened, but you have to be a glutton for hill climbing to do any very long hikes.

Kennedy Trail starts at the base of the mountains near Los Gatos and follows a fire road as it climbs up to reach Mount El Sombroso. It’s mostly surrounded by people height brush, but due to its steep dry slopes there aren’t many tall trees so views over the valley open up.

The lack of overgrowth also means limited shade, and in the summer the trail is hot. So hot that, along with the usual mountain lions, ticks, and rattlesnakes, the trail signage has warnings about signs of dog dehydration for dog walkers.

Trail Junction where Priest Rock Trail meets Kennedy Trail

The trail is popular with dog walkers, mountain bikers, trail runners, and hikers alike, and is despite its heat and steep slopes, or maybe because of those steep slopes, on a weekend you’ll likely to see all of the above.

When I arrived at the trail junction, my turn around point for a total hike of just under 8 miles with 2,000 feet of elevation change, I was greeted with the fog rolling in from the Pacific and burning off as it hugged the crest of the Santa Cruz mountains. I guess that’s why this end of range is so hot and dry and the other side of the range is lush redwood groves.