Hiking Sourdough Mountain & Lookout in North Cascades National Park
Contents
Sourdough Mountain Hike Information
Difficulty: Difficult
Distance: 21.80Km (13.5 miles)
Elevation Gain: 1,710m (5,610ft)
Highest Elevation: 1,863m (6,112ft)
Average Gradient: 15.69%
Effort/Reward Ratio: High / High
Time Needed:
– Slow: 8 – 10 Hours
– Moderate: 7 – 8 Hours
– Fast: 6 – 7 Hours
Dogs Permitted?: No
Season: Summer
4×4 / High Clearance Required? No
Scrambling / Exposure: None
Sourdough Mountain Trail
Trailhead Coordinates: 48°43’04.2″N 121°08’44.2″W
Sourdough Mountain Overview
Sourdough Mountain is a popular hike in North Cascades National Park, Washington, offering stunning views of the teal hued Diablo Lake and the surrounding peaks on a clear day. The majority of hikers will hike to Sourdough Mountain Lookout, the location of an old fire lookout and a nice spot for panoramic views in all directions. This is not the summit, however. The hike linked here will also summit Sourdough Mountain, which adds around 4km and maybe ~100m more in elevation gain to the stats for the lookout.
The majority of the hike is a fairly relentless climb in the forest thanks to beginning at the Skagit River, but thankfully the trail is very well maintained, with a steep but manageable gradient the whole way up. This allows for reasonably fast and efficient travel, especially for trail runners, which this hike is fairly popular with.
There will be no views whatsoever on the hike until you pass Sourdough Camp, a full 1,300m higher than where you begin. Even then the views don’t fully begin until you reach around 1,600m, however once they do open up they are stunning, with fantastic views of Diablo Lake and the surrounding peaks.
This route to Sourdough Mountain is best saved for snow free ascents as the trail traverses across steep slopes towards the end, which would result in some heinous sidehilling and obvious avalanche risk in winter. As such this is really only a suitable hike in the summer. There is a different, self navigated winter/spring route up to Sourdough Mountain, whereby hikers will follow the same trail up to Sourdough Camp and then hike directly up Sourdough Creek, connecting to the northwest ridge of Sourdough Mountain, rather than the southeast ridge you’ll follow on the route described here.
Backpacking is also fairly common along this trail thanks to the Sourdough Camp and also the Pierce Mountain Camp further beyond Sourdough Lookout. Dogs are not allowed in North Cascades National Park and as such puppers should be left at home.
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Is Sourdough Mountain worthwhile?
The stats for Sourdough Mountain are fairly significant, which may put a lot of people off from attempting this hike. It’s unfortunate that the trail begins so low down as most of the hike is spent in the forest with no views. Thankfully the trail is very well maintained though, so you can efficiently dispatch this elevation quite quickly.
Once you do break out of the trees the views are fantastic, with the beautiful Diablo Lake down below, and numerous snow capped peaks around. The best views are likely before you gain the ridge as you pass through a scenic meadow with unobstructed sightlines. Unfortunately the summit itself has quite a few trees obstructing the best views, and the lookout also has some trees, though still offers very nice views.
How difficult is the hike to Sourdough Mountain?
The stats for this hike are quite demanding, with over 1,700m of elevation gain total. Thankfully the majority of the gain is quite straightforward, following a well maintained trail at a manageable gradient. Fit parties will likely find it okay, but some parties may find it very challenging.
Technically the hike is very straightforward, with nothing challenging about it, at least to the lookout. The ridge to Sourdough Mountain is mostly very simple, but there is one large bluff you need to bypass on the way. On the hike in I scrambled down this bluff, but hiking back out I realized you can bypass it entirely.
Sourdough Mountain Route Information
The parking lot for Sourdough Mountain is from a paved road next to the Skagit River (see coordinates) and is thus accessible for all vehicles. There are a few buildings blocking your sightline to the trailhead across the road, you’ll need to walk behind those buildings in order to locate the beginning of the trail.
Once you’re on the trail though, there are no decision points at all as the trail only goes one way, up. The first 3km of the hike are probably the steepest part of the trail, rising around 600m for an average gradient of around 20%. There’s nothing really to note here, the trail is well manicured and very easy to follow, so just plod along and get it over with.
After around 3km the gradient eases off a little, but you still continue to ascend at a consistently steep grade. There will still be nothing of note until you reach Sourdough Camp, a full 7.5km and 1,300m higher than the start point. This is where you will cross over Sourdough Creek, though in the winter/spring when there is snow around some parties instead choose to follow the creek up and access the summit from the northwest ridge instead (this is much shorter and a safer route in snow).
After crossing the creek the trail narrows and begins a traverse across a steep slope. You’ll hike along this traverse for almost a kilometer, rising gradually as you do so. At around the 8.5km mark, or 1,630m elevation, you’ll break out of the treeline and start to get some excellent views of the surrounding peaks, with Diablo Lake more than a kilometer below. The trail continues traversing across this open meadow, which will no doubt be colorful in the fall. Shortly ahead you’ll reach a series of switchbacks as you climb steeply up to the Sourdough ridge, with the views only getting better as you go. Eventually you will crest the ridge and start to get views to the north as well.
Once on the ridge, if you are planning to go to the summit you will turn left (west), but if you are only going to the lookout you will follow the ridge to your right (east). I’ll assume you’re going to the summit first.
The route to the summit follows a broad ridge with an obvious route, much of which has a trail to follow. There is one large bluff that you should bypass by hiking around it climbers left, if you go directly over it you will need to scramble down the other side through the bushes. After this bluff it’s merely a case of putting one foot in front of the other until you reach the highest point. There are a few false summits along the ridge, so maybe check your map to determine when you’re on the actual summit as it’s not always obvious. There is usually a summit register there that should be easy to find. Unfortunately the summit views aren’t the best as there are quite a few trees around, especially blocking the better views to the south.
Once you’re finished on the summit you simply head back down the ridge and continue along to the lookout tower, assuming you are also going to Sourdough Lookout. This is a very short addition to the peak that won’t add much time, so you may as well go. The views are arguably a little better from the lookout than the summit, with clearer views of Ross Lake to the north. The trail will actually continue on from the lookout tower, heading towards Pierce Mountain Camp.
After finishing up at the lookout you simply head back down following the same route you took up. The hike down is unfortunately quite taxing on the knees and legs due to its relentless descent. You’ll be glad to reach the trailhead on this one.
When should I hike Sourdough Mountain?
This route to Sourdough Mountain / Lookout is best hiked when there is no snow on the ground, as the traverse before you gain the ridge will involve a lot of sidehilling, and also passes through considerable avalanche terrain. As such you will likely want to wait until the snowline is above 1,700m, which usually means this hike is best saved for the summer, so mid-June to mid-October perhaps.
If you want to summit Sourdough Mountain in the winter or spring when snow is around, as noted you would follow the trail to Sourdough Camp, then you’d hike directly up Sourdough Creek to the ridge and access the peak from the northwest ridge.
Top Tip
Hiking poles are useful on this one to save the knees and legs on the gruelling descent.
After your hike you may want to drive over to Diablo Lake Overlook to get a view of the lake you could see from the mountain. It’s only around a 10 minute drive from the trailhead and offers a very nice view of the lake.
