Thunder Woods Nature Trail

Overview

A mellow woods ramble with a dash of glacier-fed color, the Thunder Woods Nature Trail is a short loop that trades big viewpoints for quiet, mossy forest. It’s generally open most of the year thanks to low elevation, making it a reliable leg-stretcher when high-country snow lingers. Expect a peaceful, family-friendly stroll more than a showstopper.

Distance and Difficulty

This is a 1.5-mile total loop with about 350 feet of elevation gain and a high point near 1,200 feet. Grades are moderate with good footing overall, though you’ll encounter a short talus stretch and a few switchbacks. Most hikers take 30–45 minutes.

What You’ll See

It’s all about the forest here: moss-draped old-growth cedar and fir, nurse logs, ferns, and seasonal mushrooms in fall with the first wildflowers popping in spring. Gaps in the trees offer peekaboo looks at the turquoise Thunder Arm of Diablo Lake—its striking color comes from fine “rock flour” ground by glaciers upstream. Benches appear here and there for quick breaks. This loop is intentionally about the woods; don’t expect big viewpoints or water access on the loop itself.

Trailhead and Navigation

Park at the day-use area in Colonial Creek Campground (South) around milepost 130 on Highway 20. Walk to the campground amphitheater where the main Thunder Creek Trail begins. Follow that trail a short way and ignore the first right turn; take the second, signed right for the Nature Trail to start the loop (you can hike it in either direction). When the campground is closed, you may need a short approach walk from the parking lot. Do not park in campsites.

Best Time to Hike

Low elevation means this loop often works year-round, especially in shoulder seasons when higher trails are snowed in. Forest cover keeps summer temps pleasant and light is soft in early morning or late afternoon for photos of mossy trunks and those brief Diablo Lake glimpses. Weekdays are quieter; expect more campground traffic on sunny weekends.

Tips and Alternatives

• If you want big water features, skip the nature-loop turn and continue on the main Thunder Creek Trail to the large wooden bridge over Thunder Creek (about 1.5 miles from the amphitheater) and back for a meatier outing.
• Watch for the wooden educational markers along the loop; there are reportedly 15–16 of them—great for curious kids.
• Facilities (bathrooms, water) are in the campground’s day-use area.

Worth It?

As a destination hike, it’s modest. As a quick, serene forest walk with subtle lake peeks—especially if you’re camping at Colonial Creek or passing through—it’s a pleasant, low-commitment win.