By STEPHEN REGENOLD

50-mile race with constant rain, gloppy, peanut-butter-like mud, washed-out trails, hills and more hills (and then a few more just for good measure), and then a finish area so muddy that racers were doing “hero slides” after crossing the line to get covered in the glop as a baptism of sorts. Good times!

That’s a summary from Facebook that I posted soon after finishing The North Face Endurance Challenge 50 Mile Championships this weekend.

The official press release on the event summed it up like this: “More than 1,000 runners from across the globe braved sheeting rain, wind and muddy trails for a chance to compete in one of the country’s top ultra races.”

Both descriptions are good points of reference for the race, which was my first 50-mile ultra. The setting, the Marin Headlands of California north of San Francisco, is in the midst of an atmospheric pounding, still in effect as I write this post from my hotel room.

All the other races for Sunday’s North Face Endurance Challenge were cancelled because of potential trail wash-outs, landslides, mud rivers, and other natural apocalyptic moments.

My own personal apocalypse came around mile 35 on the near-50-mile race*. (*Due to washed-out trails, the course was shortened last minute to slightly under 50 miles.) I was a few hours into what would be an 8-hour, 59-minute ordeal when my body decided to down-shift without approval from my mind.

Every fiber in my legs felt numb. My knees were taking on a newfound ache on top above the knee caps. To fight chafing between my legs, I yanked the liner of my shorts down to reposition the fabric every mile or so.

But then hot chicken broth saved me. At an aid station, somewhere around mile 40, a volunteer scooped up a warm cup of soup and pushed a little torn-off paper cup filled with salt my way. I poured the salt in straight, followed by the dunking of two potato cubes and a couple pretzels. (The aid stations were very well stocked.)

My ad hoc stew hit me like a jolt, and I jogged out of the aid station with new resolve to pick up the pace and attack the next hill ahead.

As ultra races go, The North Face Endurance Challenge 50 Mile Championships is a marque event of each year. Top runners from around the world come for a chance at $30,000 in prize money.

I talked to Mike Wolfe, the 2011 course champion, before this year’s event. He noted the long climbs and “blazing” descents of the Marin Headlands course.

Another ultra-running figure, Bryon Powell of iRunFar.com, noted the difficulty of the Marin course. “It’s pretty out here,” he said, “but I am not a fan of these hills.”

For the first hours of my run, it was difficult to admire any of the beauty Powell mentioned, though I did immediately notice the hills. We started predawn, at 5a.m., the headlamps of hundreds of runners attempting to pierce a foggy, rainy void.

I took off in the third wave of 50-mile races, at 5:06a.m., and I ran at the front of the group for the first few miles. The trail rounded a couple bends on flat ground before busting uphill on one of Marin’s long, famous grassy seaside hills, climbing hundreds and hundreds of vertical feet into the rain and predawn black.

“Headlamps aren’t cutting it,” I heard one runner remark. The haze was thick and it obscured the glow of LED lights, creating a foggy view where ruts on the trail and puddles were all but invisible until right underfoot.

I paced slower on the uphills initially and ran as fast as I could going back down. Eliminating miles by any means was a goal for the first couple hours of the race.

As the sun rose, the sky brightened some but remained a dark gray. Rain chattered on my hood all day — I locked myself inside a lightweight rain-shell jacket as the rain came down and never quit.

Other racers wore T-shirts and arm warmers, some visibly cold. In the valleys, it was wet but manageable, as the temps hovered around 60 degrees all day. Climb a ridge and the big winds kicked in — huge gales off the Pacific Ocean were strong enough to push you along when the course twisted favorably and the wind was at your back.

Scenery emerged as the day got later. Jungle-like vegetation draped over parts of the trail. The ridgelines were exposed grassy heights that offered occasional views to ocean beaches below.

The course, a giant figure-8 that you ran twice, looped at its western point through the seaside village of Muir Beach. The misty, sleepy town was a highlight for me on the course, a fairytale-like setting in the dense fog, muted and almost silent, with vines, rainwater running down the roads in little rivers, quiet houses, and pastures with horses peeping through fence slats as runners trotted past.

With aid stations every five miles or so, I did not carry water or food. Whole spreads of energy foods and beverages were available at every stop, and over the hours I took in electrolyte drinks, GU Chomps, M&Ms, soda pop, straight water, and the aforementioned chicken broth/pretzel/potato/salt “stew.”

Near the end, as the miles counted down, I dug deep and tried to pick up my pace. But unlike a marathon, where you can push and flame out a couple miles from the finish, I felt depleted enough in the ultra to worry about bodily injury if I pushed too hard.

“Five miles to go,” a volunteer shouted at a hilltop somewhere deep into my day. The distance remaining sounded short after my long slog for 45 miles already, and I smiled, excited to envision crossing the finish line and stopping, finally sitting down to give my legs a break.

At the final bend on the racecourse, a crowd gathered, hundreds of spectators with umbrellas and raingear slicked and soaked. I heard the event announcer shouting, and I sprinted into the chute. My day was done, my race complete. 50 miles of hills, and mud, wind, rain and more and more rain. . . but worth the push and worth the hurt in the end.

—Stephen Regenold is a founder of GearJunkie.com. He finished The North Face Endurance Challenge 50 Mile Championships in a time of 8:59:17, netting 113th place out of hundreds of runners. Stay tuned for a column on some of the gear that helped him make it through.