Hike of the Month

WHATCOM COUNTY — The aptly named Rock Trail weaves between towering sandstone walls and truck-sized boulders before descending toward Lost Lake. And if you’ve hiked here through all seasons and explored every nook and cranny as Bellingham geologist George Mustoe has, you would notice one compelling detail:

“You’re walking literally at the foot of the cliff. If you held your arms straight, you would be touching the cliff face,” he says. “The close-up path to the rock outcrop — that’s a feature you don’t see in other trails around this area. You can walk for just a half-hour. It’s not a trail where you have to go a long way to get to the best part.”

Located at the highest point of Larrabee State Park, off Chuckanut Drive, the Rock Trail is considered a geological wonder and an engineering marvel in its trail design, several geologists say.

Completed last January, it’s one of the few new trails built in Western Washington in recent years, and one of the most elaborate, for sure, with sweeping stairs, a pedestrian bridge and a half-dozen switchbacks with peek-a-boo views of Mount Baker, Twin Sisters and, during leaf-free winter months, Samish Bay.

At 1.2 miles, this trail connects the Cyrus Gates Overlook at the top of Cleator Road to Lost Lake via South Lost Lake Trail. Turn right to Fragrance Lake for an additional two-mile hike.

Geology up close

On other trails, the unusual stratigraphic details of the Chuckanut Range can be seen — with binoculars. But here, you can touch the grainy surface or nose right into the cavities of the sandstone walls.

The trail showcases three rock cliffs, each at least 100 feet high, the walls pocked with cavities so large they’re like small caves.

Those cavities — called Tafoni weathering — have grown wider over the decades as moisture burrows deeper into them.

“It’s like a microclimate effect,” said Mustoe. “The weathering inside the cavities has accelerated because of the dampness.”

To allow close-up views of the unusual rock formations, the Washington Trails Association constructed a zigzagging 130-step staircase down a 400-foot ravine and then carved a path to run along the sandstone walls.

Some of the hole patterns look like a Connect Four game. Others have vertical patterns that Mustoe says were accentuated by the rainwater cascading down the cliff wall.

Hide and seek?

A few holes are large enough for a kindergartner to hide in.

“I’ve seen parents try to cram as many kids into those pockets as possible, like crowding college students into a phone booth. It’s pretty funny,” said Dave Tucker, a geologist at Western Washington University.

Tucker is researching the Rock Trail for his book “Geology Underfoot in Western Washington,” to be released by Mountain Press Publishing in 2015.

The first rock wall, by the bottom of the rustic stairs, features shale layers of sandstone and fine-grain sedimentary rock. These layers are not frequently seen in the Chuckanut area, said Tucker. “It’s a good geology stop.”

But to view those distinctive cavities, hike a half-mile to the third rock wall.

“The third is the most spectacular,” said geologist Mustoe. “It has the most cavities at eye level … and the most distinctive, circular-cavity shape.”

Along the trail are giant, moss-covered boulders, many of which rolled off the cliff during the last ice age, scientists estimate.

The trail has a T-Rex era or “Lost World” feel because the landscape seems out of scale — giant boulders, sweeping fields of knee-high sword ferns and towering Douglas firs. And the light in these woods. During summer and early fall, when the conifers are lush and green, rays of sunlight shoot between the firs to create a surreal glow.

But if you want to see a dreamlike world, Mustoe recommends hiking here in winter, when sunlight penetrates the barren maples and alders to bring out details in the rock formations. In February, the sandstone is draped with icicles.

Tan Vinh: 206-515-5656 or tvinh@seattletimes.com. On Twitter @tanvinhseattle