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Hiking Sourdough Mountain Trail in the North Cascades is a great way to spend a day and is a bucket list adventure for most. This trail is about 11 miles out-and-back and leads to one of the most spectacular views of Diablo Lake! If you are unfamiliar with Diablo Lake, it’s a glacier-fed reservoir that is a jaw-dropping bright blue hue. The trail begins in a lush forest and then climbs through alpine meadows and granite boulders with stunning views of Mount Shuksan, Diablo Lake, and other mountains. At the summit sits a lookout tower which is actually the site of one of the first lookouts built by the U.S Forest Service in the early 1900s. The lookout was reconstructed in the 1930s and is still such a special part of Washington’s history.

Sourdough Mountain Trail

Located in the North Cascades National Park, Sourdough Mountain Trail is an out-and-back trail that leads you to the summit of Sourdough Mountain which is 7,000 feet above sea level and offers incredible views of the North Cascade mountain range and Diablo Lake, which serves as your destination after working up some sweat on this strenuous trail! The trailhead can be a bit tricky to find, but it’s located near Gorge Lake Campground right off Highway 20. It’s a 2.5-hour drive from Seattle and if you’re coming from Eastern Washington then you’ll have to wait until late Summer or Fall when the eastern sections of Highway 20 reopen after the winter closures. 

This trail is definitely not recommended for beginners and should be taken seriously. But by no means does this mean that a beginner cannot enjoy this hike - I’m certainly still at the beginner level and both loved and hated this hike! It’s a long, strenuous hike that may take anywhere from 8-12 hours depending on your pace and fitness level. Even though this trail is between 5-6 miles each way, the elevation gain is close to 5,000 feet! There are many steep inclines along the way so it's important to wear proper shoes that can support your weight and protect your ankles from twisting or rolling over. Also, bring plenty of water with you because there aren’t many sources along the way! If you want to opt for an easier trail, check out Diablo Lake Trail which is about 7 miles and has much lower elevation gains. As always, be sure to download a map of the trail from the Washington Trails Association or Google Maps. 

The Best Time to Hike the Sourdough Mountain Trail

The Sourdough Mountain Trail is open from June to mid-October, but the best time to hike it is in late summer or early fall. The road leading up to this area is closed during winter months so make sure you plan accordingly. During the summer months, you'll find tons of wildflowers along the trail after the first four miles where the trail opens up to a large meadow. This is one of my favorite hikes in the state, and it's well worth the drive up here. On WTA's website and AllTrails, you can check the trip reports to see if there are flowers blooming or animal and bug spottings from fellow hikers. You can also camp at nearby Pierce Mountain Campground which has plenty of spots available during summer months and you’ll need to pick up a Backcountry Permit from the Wilderness Information Center for $26 to camp within the North Cascade National Park. 

To help you enjoy your hike as much as possible, here are some tips for hiking Sourdough Mountain Trail!

Tip 1: Pack a Water Filter

This is a good idea in general, but especially so if you're hiking in the North Cascades. The air is often dry and dusty, so it can be difficult to get enough water from your surroundings. Make sure that you pack a water filter with you so that if you run out along the way, or just want to refill your bottle at any point along the trail. Ideally, you should bring at least 1 liter for each person in your party, but 2 liters per person is highly recommended if you're hiking at high elevations. As beginners, we didn’t do a ton of research beforehand and only brought one large water bottle per person - you know, the typical 32oz Nalgene bottle. Needless to say, it wasn’t nearly enough water! We had all pretty much depleted our water before we hit the 4-mile mark, and luckily we ran into a couple at the glacial stream that were refilling their water bottles using a filter attachment and they were nice enough to refill ours for us. Lesson learned, invest in a water filter for hiking and never hike without one!

Tip 2: Pack Snacks

The Sourdough Mountain Trail is a great place to hike with friends and family, but it's also a good idea to pack some snacks because no one likes a grumpy hiking buddy. The trail is long and you'll want something to eat along the way, so bring something light that will fill you up without weighing down your pack too much. I suggest packing a sandwich or wrap and stopping to eat that halfway up the trail and then bringing along a granola bar or protein bar and some fruit. If you're looking for a snack that will keep your energy levels high while also satisfying hunger pangs, look no further than nuts! A handful of almonds or cashews provides protein as well as healthy fats.

Tip 3: Bring Walking Poles

Walking poles are a great asset on the Sourdough Mountain Trail. They can help with balance on steep sections and provide assistance for both uphill and downhill sections. If you're not sure whether or not to bring them, just do it! You'll be grateful for the extra support when climbing up those long switchbacks at high elevation (which often have loose rocks). We didn’t have any for this hike, but passed many other hikers along the trail that did. It would’ve made things a lot easier if we had them, especially to help with the downhill portion of the hike. 

Tip 4: Take Your Time!

Sourdough Mountain Trail is more suited for advanced hikers, but if you're more intermediate or beginner, go slow and make a day of it. There's plenty of scenery to enjoy along the way! This hike is typically completed in 8-12 hours and you'll want to take in all of those views along the way -and there are many! You're also achieving a lot of elevation gain on this hike so the increase in altitude can make it more difficult to catch your breath as you continue up the incline of the mountain. I typically don't take too many breaks while hiking, but I found myself needing to stop every 20-minutes or so on this trail due to the elevation gain. 

Tip 5: Listen to Your Body & Take Breaks

It's important to listen to your body and take breaks when you need them. If you are sore or in pain, stop and rest. It's better to take a break than push through the discomfort and end up with an injury that could keep you from hiking for days or even weeks! If you can prepare your body a week or two leading up to this hike, try to do so. As I mentioned earlier, this hike is quite intense and you will be sore for about a week afterwards. Be sure to take breaks and stretch before, during, and after the hike and be kind to those muscles that worked so hard to get you up that mountain!

Tip 6: Enjoy the Views!

Be sure to take in all of the beautiful scenery on this trail. You'll have a chance to enjoy views of Diablo Lake and its surroundings, including snow-capped mountain peaks, Diablo Dam, and Ross Lake. There are also great places where you can stop along the way and take photos of your friends or family in front of some iconic Washington scenery. The views make this hike absolutely worth it and it’s one of the best rewards for making it up the trail. The views on this hike are forever imprinted in my mind and are truly breathtakingly beautiful! If you have enough time after your hike or if you're spending the weekend in the area, be sure to visit the viewpoints of Diablo and Ross Lake along the state route, and you can even go paddleboarding or kayaking at Diablo Lake!

Happy travels!

- Tess

Tess Arnold

Hi! I’m Tess, founder of TravelingTessie.com, and not only do I love to travel, but I love immersing myself in new places and finding off the beaten path experiences wherever I go! I’ve lived in 4 different states & traveled to 13 countries and counting. I believe that tourism is meant to benefit both visitors and locals alike—and I want to bring that idea back into the travel industry by highlighting companies run by locals such as tours, hotels, restaurants, and more. On Traveling Tessie you can find hidden gems in top destinations around the world, travel tips, detailed city guides, and tons of inspiration for your next trip!  If you love travel as much as I do, then please join me on this journey! I hope you enjoy my content as much as I enjoy providing it for you!