[Updated as of 2/10/12: Check out these recommended upcoming trail races on Diablo: April 21 Diablo Trails Challenge by Brazen Racing to benefit Save Mount Diablo, July 7 Mt. Diablo Trail Run by Inside Trail Racing, and Sept. 15 Diablo Trail Run by Coastal Trail Runs. All three events offer varying distances, 50K and shorter.]

Last Friday I spent the better part of the day running over and around one of Northern California’s most spectacular and perhaps under-appreciated mountains: the double-peaked oasis in suburbia known as Mount Diablo. Its trailhead is a mere half-hour from my home, yet I make it over there only a couple of times each year to run. Diablo tends to cross my mind as an afterthought—an image in the rear-view mirror while Mount Tamalpais beckons across the bay.

But every time I do Diablo, I want to return for more. The mountain rises from a couple hundred feet above sea level to 3849 feet, revealing views that on clear days stretch some 200 miles and glimpse the Sierra. From wide-open fire roads to shady single-track, Diablo offers an abundance of diversity in terms of terrain and wildlife. In addition to the usual suspects like deer, hawks and coyote, I’ve spotted a few bobcats, numerous tarantulas and clusters of ladybugs out there.

Coming up on Sunday, November 6, is one of my favorite events on the mountain: the Diablo Trail Adventure Half Marathon/10K/family hike to support Save Mount Diablo. This year, SMD celebrates 40 years of preserving open space and fighting suburban sprawl. The group’s hard work has increased the amount of protected open space from less than 7000 to more than 100,000 acres.

I have run the Diablo Trail Adventure numerous times and am reprinting a race report below from one of the more memorable years. I also recommend SMD’s 50K in the spring. Or, you can pick up a map from the Mount Diablo Interpretive Association and do some or all of the route I did the other day (much of which covers the half marathon route):

• Start at Castle Rock Park Trailhead in Walnut Creek
• Head out on the Briones-Mt. Diablo Regional Trail
• Go up Wall Point Road
• Drop down to Rock City for water
• Go up, up, up the Summit Trail to the Summit
• Back down to Devil’s Elbow
• Round the peak counterclockwise on North Peak Trail, Prospector’s Gap, Meridian Ridge Road, Deer Flat Road, all the way to Juniper Campground for water
• Backtrack to pick up Burma Road. Stay on Burma all the way down until left on Buckeye Trail
• Right on Stage Road and all the way back to Castle Rock through Pine Canyon. Total mileage: 25

That’s just one of countless worthwhile routes. Starting at Mitchell Canyon Trailhead in Clayton is my other favorite option, but it takes longer to drive there.

I lucked out with mild temperatures, dry footing and calm wind while running there last week. But Diablo’s weather can range from snowy to scorching, and it’s famous for wild winds and gooey mud.

I wrote the report below in November of 2008, the one year I opted to do the Trail Adventure’s 10K instead of half marathon, because it was my first race back after months off to heal a broken foot. I’m still debating whether to do the half marathon this November 6, but chances are I will.

The 2008 Mount Diablo Trail Adventure

(or: How Sarah Started Barefoot Running Before It Was Trendy)

I was in the middle of a 10K race on Mount Diablo that felt like a nightmare. My feet were weighed down, I kept slipping and almost falling, and I was reduced to running in slow motion as though sloshing through waist-high water. The nightmare’s monster had a three-letter name: MUD. It grasped my soles and kept adding more and more clumps of clay until the bottom of each shoe was caked with at least six inches and five pounds of dark, sticky, cement-like soil. Halfway, around mile 3, I was in the lead but my closest competitor caught up. Our duel in the dirt would come down to which one of us could master the mud.

I didn’t expect the race to be dramatic. I had chosen Save Mount Diablo’s Trail Adventure as a low-key, below-the-radar return to racing—my first race in five months, since the broken foot in June.

We took off on the dirt Stage Road along Pine Creek. The area felt wonderfully familiar; I love the shade of the oaks we run under and the creek crossings we hopscotch over. A downed tree forced runners to line up and take turns bending over to thread the needle through horizontal branches. The footing was fine in this first stretch, but then as we split off from the half-marathoners and turned onto the big connector hill toward Wall Point Road, I spotted mud ahead of me and another woman close behind. I ran up the steep hill, pulling ahead of a pack of about five guys. We left the forest and entered the rolling meadowland of Macedo Ranch, the final three miles of the 10K. And that’s where the mud monster started to attack.

I have conquered mud in the notoriously muddy Catalina Island and Golden Hills marathons, but never have I encountered mud this gruesome. As the conditions went from bad to worse, I kept cursing my shoes. They were old and worn out, and their knobby bottoms gripped the dirt. I’d love to be done with them, just ditch them then and there. A-ha! It would be a gamble to do what I was thinking of doing, but what’s the worst that could happen if I took off my shoes? My feet would hurt. So what? Then I’d have a legitimate excuse to limp home and end this sorry excuse for a run.

I barely stopped my stride and didn’t bother untying the laces; I yanked one off, threw it to the ground, yanked the other off, chucked it next to the first one, and got right back to running with my socks still on, not looking back at the runners behind me. I felt like Clark Kent ripping off his suit or Brandi Chastain ripping off her shirt—I broke free, here I go!

A few steps into it I realized my feet actually felt good. The mud formed a smooth, springy footing, firm enough for running, like on a beach right next to the water’s edge. I pulled farther ahead of the woman behind me and reeled in a guy. The next mile and a half I ran as hard as I could, on hills that felt like the surface of a cloud.

I wish it could’ve ended at mile 5.5, but in the final three-quarters mile, the mud from the meadow gave way to a dry and pebbly road. Then it turned to sharp gravel. I thought of people who walk on shards of glass or hot coals—their trick is to go fast, becaue if you slow down, then you get poked and burned—so I sprinted and winced the whole way to the finish. I couldn’t believe it—I actually won! I was first female and third overall in just under 52 minutes.

My family showed up to surprise me at the finish. My daughter was the first to notice my stocking feet and ask, “Where are your shoes?” My husband said, “Are you insane?”

I didn’t feel crazy—just grateful to be out there running again, injury free, and having the most ridiculous, up-and-down-and-up-again 10K ever.