By TIM WILCOX

Special to the Alpine Mountaineer

Where: Outskirts of Lake Arrowhead

Length: 4.5-mile round trip

Elevation gain: 1,100 feet

Challenge: moderate to difficult

Let’s begin with a simple declaration: This is a hike! Rising more than 1,000 feet from the trailhead and winding around and over myriad boulders, The Pinnacles Trail is one of our area’s most challenging routes. Because the setting is more high desert than forested mountain, it offers a refreshingly different outdoor experience. It’s a shadeless hike and, during summertime, a relentlessly hot one, too. As we’re transitioning to fall, though, the comfort level is much higher.

The trailhead is north of the lake near the end of Highway 173. From the big Caltrans wall project below Mountains Community Hospital, it’s about six miles. You also can access this meandering stretch of Highway 173 from North Bay Road.

On the Trail

Watch for the trailhead sign on the left about a mile after you’ve passed the highway’s intersection with Grass Valley Road. Pull in there and, with Forest Service requirements in mind, display a daily or annual Adventure Pass.

About one-tenth of a mile in, you’ll come to your first striking view of the oh-so-rocky Pinnacles. As you proceed along the trail, the impression builds that this could be the most extensive boulder field—or series of fields—in the San Bernardino Mountains. It’s reminiscent of Joshua Tree National Park.

As for vegetation, chaparral predominates in the company of a few brave pines. Farther uphill, however, it’s exclusively chaparral.

Two-tenths of a mile from the trailhead, you’ll come to a fork in the path. Bear to the right. At this point you’re ascending gently. Soon you come to an area where the path seems to head off in several different directions. Your best bet is to continue heading toward The Pinnacles. Don’t be distracted by ancillary routes.

The trail narrows to an average width of about three feet and, thre-quarters of mile in, starts ascending more dramatically. Just past the one-mile mark, you’ll need to be especially trail aware once again as the route is interrupted by large rocks and a dry stream bed. Watch for the beaten path and stay on it. It narrows to a foot in spots, thanks to the impinging shrubbery.

Natural rock formations along the trail are eerily reminiscent of the monumental stone sculptures on Easter Island.

Now the most challenging part of the hike begins. Increasingly, you’ll need to step around and even clamor over boulders that obscure and obstruct the trail. Small piles of stacked rocks (“cairns”) on the boulders, left by thoughtful hikers, signal that you’re on track.

Be especially careful from this point on as, more and more, you’re challenged to climb over boulders—some of them quite large. A fall could easily result in serious injury. That said, common sense (Is it common?) suggests that you avoid hiking this trail alone.

Slightly more than 1.5 miles from the trailhead, where the path levels out briefly, you’ll come to an iron post pointing you in the right direction. Turn around for a moment here and savor mountain views to the east and southeast.

Now, proceeding with abundant care up the seriously rocky route, you’re approaching The Pinnacles’ lower summit. Here the boulders looming overhead, while no doubt stationary for millennia, appear poised to tumble without notice. It’s a slightly unsettling illusion.

Finally, exactly two miles from the trailhead, you’ll be looking up at the principal summit. In the foreground is a large boulder bearing a natural mark that looks like a plus sign or a cross. Welcome it as a portent that you’re near hike’s end. Slightly more than two-tenths of a mile farther, all of your climbing and clamoring will be rewarded with panoramic views of the mountains and high desert. It’s a breathtaking buena vista.

When you head back, take it slow and easy—especially through the upper boulder field. Be mindful of each step. There’s absolutely no need to risk an anticlimax to what should be an invigorating and memorable hike.

NOTES: The Pinnacles Trail offers a refreshing change of scene from most of our mountain hikes and also is one of the most challenging routes. The need to scramble around and over boulders, particularly during the upper one-third of the trail, makes it a potentially dangerous foray. Special caution and sturdy hiking boots are mandatory. Solo hiking is discouraged. Views at many points are spectacular.