If you want to escape the heat and see something cool, take a two-hour drive and short walk to the mouth of Boulder Cave.
Just 32 miles west of Naches, on the way to Chinook Pass, this short and easy 1 1/2 -mile roundtrip hike is great for families with kids and those not in the peak of fitness.
The cave was discovered by prospectors 116 years ago.
Instead of being made from limestone or a lava tube, Boulder Cave was made when Devil’s Creek eroded sedimentary gravel deposits that were incorporated into lava flows some 10 million-12 million years ago. When the water carried away the sediments, it left a hollow pocket about 350 feet long and 30 feet wide. About 25,000 years ago, the outer edge of the opening weakened and the ceiling rock collapsed, allowing the cave entrance to form.
If you go: From the Tri-Cities take Interstate 82 west through Yakima. Take Exit 31 off I-82 and head west 48 miles following US 12 and heading west on WA-410, toward Chinook Pass. Make a left at Old River Road. Cross a bridge over the Naches River and almost immediately turn right onto Forest Road 1704. Drive 1.2 miles and enter the Boulder Cave Day Use Area at the sign. The trailhead is on the left of the day use area as you drive in. Distance: 0.75 miles each way, 1.5 miles out and back. Difficulty: Easy 1 out of 5. Elevation gain: 200 feet. Parking lot and day use area available. National Forest parking permit required. Rest room facility available. The trail begins behind the kiosk. Dogs on a leash OK.
The trail was built in the 1930s by the Civilian Conservation Corps and has been improved many times, most recently in 2014.
From the parking lot, follow the well-packed and clearly identified trail along the edge of the small ravine in which Devil’s Creek flows. It’s a short walk that climbs gently and steadily up. Paintbrush, lupine, desert parsley, penstemon, vetch, sedum, wild rose, onion and strawberry are some of the many wildflowers along the path.
A platform offers views upstream and downstream in the ravine, and several interpretive educational signs on the path describe the geology and ecology. The forest is composed of second growth ponderosa pine, Douglas fir, western larch and grand fir. There are signs that explain the role of fire and how to identify the trees by their needles and leaves. Another sign explains the importance of the native plants with medicinal value to the American Indians: the Oregon grape, Vanilla leaf and yarrow plant.
After about half a mile, you go over a crest and can then descend down to rock- and tree-fall-filled ravine with a waterfall at the upper entrance to the cave. If you look up toward the waterfall, you’ll see a young cave beginning to form.
Follow the sign to the right to enter the cave. The cave trail goes 400 feet underground, so bring a flash light and take your time walking carefully. Once inside, turn off your flashlight and enjoy the unique experience of being in absolute, total blackness, right next to a rushing underground stream.
After 400 feet, you’ll come out at the downstream end of the cave and be able to return back to the parking lot on the same trail you came in on. The views up the canyon walls from the observation platforms are impressive, as are the intense bright colors and variety of green, yellow and orange lichens and moss growing on the rock walls.
The cave is the winter residence of several species of bats, including the Pacific western big-eared bat, and the rare Townsend’s big-eared bat. There are no bats in the summer. But please stay on the trail, don’t touch the cave walls, try to keep the flashlight beams off the ceilings and respect the seasonal closure.
If you want to extend your hike a little bit, you can follow a trail above the cave to the top of Devil’s Creek Falls and beyond. It’s a steep scramble and the trail is very close to the edge of the ravine, so be careful.
Paul Krupin is an avid local hiking enthusiast, retired environmental specialist, and a member of the InterMountain Alpine Club (IMAC). He has been hiking the trails of the Pacific Northwest since 1976. Find out more at the IMAC Facebook or Meetup pages. He can be reached at firstname.lastname@example.org.