Sourdough Loop (North Cascades)

This past Monday was hot and sunny, and it seemed like a great time to visit the high country in search of views and cooler air. I decided to do the Sourdough Loop, as described on the North Cascades National Park website. This loop wasn’t possible for awhile because the bridge across Diablo Lake was out. But they repaired the bridge this winter, and now you can make a loop by heading up the Sourdough Mountain trail to the Sourdough Lookout, and then dropping down the other side via the Pierce Mountain trail. Eventually the Pierce Mountain trail intersects the Big Beaver Trail, which connects to the Diablo Lake trail and ultimately deposits you back where you started, in the little town of Diablo.

The Sourdough Mountain trail is a steep climb, particularly the first couple miles, but the good news is that it’s currently in great condition. There are zero blowdowns, and the trail is essentially snow-free until the very top, when you hit the ridge. Once on the ridge, there is nearly constant snow. However, I was on the ridge at 900 am on a sunny day and the snow was just about perfect – firm and consolidated but still soft enough that I didn’t need traction.  The views at the top are outstanding, the trail is easy to follow (even when it hits snow), and Sourdough Mountain make a great day hike in and of itself.

 

Pierce Mountain trail is a different story. The first mile or so of the Pierce Mountain trail from the Lookout is still buried under snow, but unlike the Sourdough Trail, there is no obvious track. I used a combination of intermittent cairns, a faded set of footprints, and map/GPS to make my way down the east ridge on the Pierce Mountain trail. There were a few steep sections, but the snow was soft enough to plunge-step and the runouts were mostly gentle.

 

At 5400′, the Pierce Mountain trail starts to reappear in places, but it’s not until 4900 ft that it’s completely clear. And by completely clear, I mean clear of snow. Definitely not clear of brush. When I checked my GPS it showed that I was significantly off-route, and the trail was rough enough in places that I briefly wondered if I’d missed a turn. However, I was going in the right direction (down the mountain) and the trail had clearly been maintained at some point, so I stuck with it, and sure enough, eventually I confirmed that I was indeed on Pierce Mountain trail. It’s just not where it’s supposed to be, according to the Earthmate map. Technology – it’ll getcha every time.

One of the nice things about this loop is that you get all the hard stuff over at the beginning. There’s 6300 ft of elev gain for the loop, but 5000 of that happens during the first 5 miles up to Sourdough. Even Pierce Mountain ultimately turns into a mellow trail through the woods. Big Beaver and Diablo Lake trails were smooth sailing with minimal blowdowns, no snow, and no route-finding issues.

One important note… make sure to fill your bottles before you start your descent off Pierce Mountain. The trail is dry as a bone until you hit a small stream just past Ross Lake Resort. I ran this section mid-day, temps in the high 80s, and I was so glad to see that creek near the resort.

The final miles on the Diablo Lake trail are lovely. Shaded, cool, and the perfect end to a run. Unfortunately for me, I had started at the Sourdough trailhead and therefore still had to run a couple miles of road between the Diablo Lake TH and the Sourdough TH.

In hindsight I wish I’d started at the Diablo Lake TH and gotten the road section out of the way first. The road also would’ve made a nice warm-up before you start the steep climb up Sourdough. Which reminds me – you’ll probably want to bring a map that’s detailed enough to show the trails/roads near Ross Dam and Diablo Dam, as things could get a little confusing. I’m sure you could figure it out by wandering around, but why log extra miles on the road when there’s all that trail to explore?