Sourdough Mountain Trail

HARD 47 reviews

Sourdough Mountain Trail is a 9.1 mile lightly trafficked out and back trail located near Marblemount, Washington that features a river and is rated as difficult. The trail is primarily used for hiking, walking, nature trips, and birding and is best used from May until October.

9.1 miles
5,104 feet
Out & Back



nature trips





wild flowers



no dogs

Directions from Ross Dam Parking Area: Travel west on Highway 20 to mile marker 126. Turn right and cross the Diablo Dam. Drive into the community of Diablo and park near the enclosed swimming pool. The trail begins behind the pool.

2 days ago

A late start at 2:45 on a mostly sunny warm day. I only hiked until 5 and then turned around, only because of the late start. This is definitely a strenuous trail, more on the downhill trip. Fantastic views at a couple of places where the trees thin out. I am going to try this trail again and being trekking poles to help on the descent. The pics at the top seem to make the trip worthwhile.

16 days ago

Best views ever. Worst descent ever.

Hiked yesterday, 8/2/18. Getting into the park around 9:45 AM, the ranger said I best hurry if I wanted to make it to the top before potential cloud coverage that would prevent any views. With this in mind, I hurried over to the trail and made my way up the never-ending wooded switchbacks, occasionally peering out through the trees to see already-impressive views.

Multiple times I figured I was close to getting out of the trees, but the wooded switchbacks were endless and steep. Getting to the creek by the Sourdough campsite, I stopped and filtered some water to keep fully stocked.

This is when the hike really starts getting worthwhile. The views open up to the right down onto the bright, turquoise lake as wildflowers start to populate the fields and the incline tapers off a bit.

A few more switchbacks until the top, and then you are greeted by the most amazing views on every side of the mountain. Glaciers, jagged peaks, rolling clouds, mountain lakes, and even more jagged peaks off on the horizon that made me yell to myself “WHAT ARE THOSE!!!” as I was only sharing the top with one other hiker. You could spend the whole day up there with a set of binoculars picking apart every bit of the scenery.

Now for the worst part. The hike was incredibly steep on the way down too (who would’ve thought), and the return of trees to prevent views really made me hate myself. I made it up in around 3 hours, and ended up only shaving off about 20-30 minutes due to just how painful it was on my knees. USE HIKING POLES TO SAVE YOURSELF.

The views were second-to-none, but the hike down was a special type of hell.

Edit: forgot to mention bugs. Weren’t an issue on the way up, and usually don’t bother me much in general so I never use bug spray. They were a bit annoying for the final stretch on the way down when I started taking breaks - so would probably be terrible for those that attract bugs. No mosquitos, just lots of little gnats and flies.

21 days ago

The hike starts out very steep, going through a forested with very few openings for views. Because it is so steep and difficult, it is hard to keep motivated with redundancy of forested switchbacks. Once you come out of the forest, the views are stunning, but the steepness of the hike is relentless. You will cross Sourdough Creek which is very refreshing and a good place to refill water. Then you continue to the top where you will cross some snow fields and hit the lookout. The view of Diablo Lake was perfection, capturing the turquoise color.

My biggest complaint, which is not the trails fault, but the bugs were the worst I have ever seen. We got over 100 mosquito bites each and they did not care what clothing or bug spray we were wearing.

Advice — take your hiking poles. They are super helpful on the way down and will give your knees some ease.

21 days ago

Beautiful hike. We used our hiking poles to save our knees coming back down. Bugs at the top were awful and prevented us from sitting down to relax and enjoy the view. The 360 pano from up top is unreal though.

1 month ago

Elevation gain is pretty much unrelenting however it seemed to be the steepest to start the hike. If you have ever wanted to hike a mile... up... here is a perfect chance to. Views from the top and steep meadow before are excellent.

1 month ago

What the guy said below. The snowfields at the top still have some vertical gain so our poles were helpful but did it in hiking shoes.

1 month ago

Hiked on July 3, 2018. The trail gains elevation rapidly from the start and only lets up for small portions of the hike. Three separate snowfields are still present during the last third of the hike, but are easily passable with hiking boots. It might be worth bringing yaktraks as well.

As others have said, the hike is quite difficult but doable with a little motivation. The trail is actually ~10.4 miles roundtrip, as indicated at the trailhead. Someone should change the info above to reflect that. Start earlier in the day to leave yourself plenty of time. Views from the top are downright spectacular, and worth the long hike up.

1 month ago

June 24, 2018: This trail being rated "hard" is no stretch of the imagination, it lives up to that classification. Found out today why it's lightly trafficked; it is brutal if you're not in peak shape. Bring plenty of water your leg muscles will thank you. The few snow fields toward the top are easily passable with hiking boots thanks to previous hikers paving the way.
Overall it was a straight forward out and back. Being so steep, the trek down is has its own special kind of charm, turning into leg workout 2.0, and does wonders on your knees (sarcasm). The views at the top are spectacular. There are other easier hikes with pretty scenery, but what sets this one apart is the sense of accomplishment when completed.
I recorded 10.6 miles total, never leaving the trail. The only thing that would add distance was the little extra walking around in circles at the top to take pics, but it certainly wasn't 2 miles worth. Either my recording was wrong or this trail is a little longer than 8 miles.

5 months ago

Make no mistake, unlike many other hard-rated hikes on this website, this one is actually hard. An information board in one of the ranger centers rated it as extremely strenuous, and while I'm not sure about the "extreme" part, "strenuous" is definitely an apt description.
You start straight off with the hardest part - very steep switchbacks through a forest that feel almost endless and offer absolutely no views to take your mind off your misery. While you gain a lot of altitude in this section, on the map it looks like you are making no progress at all, which can feel somewhat discouraging. It was warm and really humid when we did the hike, which made the first part even worse.
Once you make it beyond the switchbacks, you finally get some views, which gradually open up until you have full 360 at the top. The final push again comes in the form of a few steep switchbacks but this time they are fairly short.
Mid-July, there was still a lot of snow at the top, so sturdy boots and hiking poles are a must.
During the whole hike, we only met 3 or 4 other people, so if you want some quiet time, this hike is definitely a good place. We saw some ground-squirrels and bear footprints but no other wildlife.
In sum, this is a great hike with stunning views at the top, definitely worth the effort.

10 months ago

super steep nice view at the top but it's a climb.

11 months ago

This is one of the most beautiful hikes I have ever done! The views at the top are absolutely breathtaking. I would recommend starting as early as possible so you have time to enjoy the views at the top before heading back down. Bring lots of water. It is a very difficult hike with endless switchbacks. I did it in early September, the weather was perfect and there were still wildflowers. The trail was not crowded at all. Highly recommend!

11 months ago

Offered everything a great hiking trail should: steep ascent to the summit on a root, rock and loose soil trail.

STEEP from the get-go with switch backs to the 2.5 mile mark at which point the trail straightens out a bit and the grade eases slightly to Sourdough Camp. After crossing the dry creek at the camp, the switchbacks return for the second climb to the summit.

Great views at the top!!

Jorayne S. set a great pace that put us at the finish line in 3.5 hrs and 2.7 hrs to descend.

11 months ago

C'est vraiment une randonnée longue et difficile. 4h de montée et 2h30 de descente. Mais la faune et le panorama valent l'effort ! Vu 4 biches dont une qui était à 2 mètres de moi. Et surtout vu un ours noir au sommet, il était très proche à 20 mètres. Il mangeait des fruits. Et ce paysage... incroyable randonnée.

Saturday, August 19, 2017

Most incredible, gorgeous trail and views I've seen yet! The alpine meadows were in full wildflower bloom and Diablo Lake was a turquoise jewel. Ross Lake and soo many peaks are viewable in 360 fashion from the peak. We came within 20-50ft of 3 bears so make noise and bring spray. I recommend taking poles for the walk back. The last 2 miles down felt awful on the knees and I would have likely had some real pain without them! Other than knee misery otw down, loved this hike, would do it many times over. Plus you can swim the next day in the pristine lakes!

Tuesday, August 15, 2017

What a ride! Steep as hell, rocky, sandy and narrow but so fullfilling when you hit the peak and have a beautifull clear view of the area! It was magical! We were lucky the smoke rained down the 2 days before the hike. Defenitely recommend this hike. Bring enough water/food supplies with you because refilling isn't really possible, maybe at 1/2 places. And I would bring hiking poles, they make it rasier for you.

Friday, August 04, 2017

It took me 3 hours to get to the top and to the fire lookout. The lookout has a padlock. With a filter and two 32oz water bottle you should have more than enough water. In the evening it was 88 degree but as you climb higher the temperature drops to around 69 degree. The mountain visibility isn't too great because of the fires that are coming from the north but the stars are very bright since you are above the smoke. It took me around a hour and a half to get back in the dark. Saw one bear that was pretty awesome. Also, if you plan to camp there, there is a lot of open space for tents around the lookout. I would wait a couple of days so that the smoke dies down or go during the night because the stars are so vibrant.

Monday, July 17, 2017

As the previous posts have stated this hike is no joke. This was the most difficult hike I've done to date. Took about 3.5 hours to reach the fire lookout. The first 2.5 hours of the hike are the hardest, and consist of steep relentless switchback that make you question your life choices.

You'll reach the sourdough camp ground at the stream, you'll need to cross the stream to pick up the trail which is denoted by a cairn. The views open shortly after this.

The views are amazing and make the hike worth doing. At the summit, Ross lake is visible and worth seeing.

Bring lots of water, I went through 2 liters and wished I had more. Bear spray is also a must, lots of fresh scat on the upper portion of the trail.

Thursday, July 13, 2017

The hardest part is definitely the first 2.5 miles. Bring bear spray as they are grazing the meadows. Snow at the very top still but the entire trail is clear from trail head till past the second meadow.

Sunday, July 09, 2017

Hardest hike I've ever done. That being said, you will be rewarded with some of the best views in all of the PNW at the lookout. Bring plenty of water as it is a steep incline pretty much the entire 5-6 miles up, however there is clean running water along the way. Still a lot of snow at the very top but it was relatively easy to traverse. As I said, be prepared to spend 7-8 hours of grueling work on this hike, but it's worth it.

Tuesday, July 04, 2017

Hiked on July 2, 2017. At trailhead at 10:40am, took 5 hours to get to the Fire Lookout. 5.1 miles and 5,000+ ft of elevation gained. Fire lookout is closed, and I don't think it will be open anytime soon, so do not plan to sleep in it for an overnight hike. There was some snow around the river crossing near the 4,500' elevation mark . It was tough to see the trail at times, but just follow the boot marks in the snow and you'll be okay. The trail was mostly snow free after the river crossing. The only part that was a little sketchy was crossing the river. The snow was thick and hard pack, but was safe. Lots of snow at the Lookout still. This hike is no joke, very difficult with nothing but elevation gain all the way up! Saw a nice cinnamon black bear near the fire lookout. Plenty of clean water streams from the very bottom to the top all along the trail.

Tuesday, June 20, 2017

Amazing views there is a side of a mountain with 5 large waterfalls as you hike up. Also, I made it to Sourdough campground but there was a lot of snow still so I couldn't find the trail. In a couple of weeks you should be able to get to the top no problem.

Wednesday, June 14, 2017

Today it was done! Realy hard elevation in the first part of trail. About 1000 m for 2,5 hour with the water pauses. We made just a half of trail and come back. No snow. Some good views on the top.

Thursday, May 11, 2017

This trail was no joke! The entire trail is uphill with absolutely no flat areas. Very difficult but worth every bit of pain. The view from the top is great, and the feeling of accomplishment that I got when I finished was one of the best feelings I've gotten from hiking. Take extra water! ;D

Tuesday, May 02, 2017

Only went 2.5 miles up (~1 hour in) since snow made the trail impossible to find after that point, but it was still a good (and tough) hike with my backpacking gear. A few notes here:
- At no point was the trail level...definitely not a walk in the park
- There were no real trail markers (other than at the beginning), a topographic map would have been helpful to find the trail
- Come back in August when the snow melts and you should have no problem day hiking this
- From the start of the parking lot to the lookout house is 5.2 miles according to the trailhead, so a total of 10.4 miles rather than 8.2

Wednesday, February 15, 2017

Did not make it to the top, got to about 4500ft, but still got some amazing views from there. Got mountain, lake, and wildlife. The trail is switchback for the first part and then just a straight, steady incline from there. All steep.

Monday, September 05, 2016

Great hike!!! Definitely go do this! Amazing views all around. Garmin watch tracked us 5.2 miles up and 5.2 miles back. Took a total of 6 hours with brief water and snack stops. Lookout tower at the top.

Sunday, June 26, 2016

My group Hiked the trail to the campsite, set up camp, then hiked to the look out. We stayed the night and then hiked down. The trail was Steep but well maintained. It has been Recently cleared of fallen trees and debris. We recommend trekking poles for the trip, especially for the way back down. The snow at the camp pads is cleared away, but there is still snow along the ridgeline on the way to the lookout. Campsite is along the left side of the main stream.
Camp Grid N48 44.690 W121 07.757
Four stars due difficulty vs reward gained.

Wednesday, May 18, 2016

We didn't make it to the top on account of rain, but we enjoyed the parts we did. Really steep, switchbacks. Great work out with beautiful mountain and lake views through the trees.

Monday, June 15, 2015

The trail is steep for the first two miles, and the switchbacks are seemingly endless during that time. Trail conditions are decent and the 5-6 downed trees are easily passible. The trail was free from snow below 5000ft, and the remaining snow at the top was easily navigated. The campsite was in good condition and the views were great from the top.

Sunday, May 17, 2015

This is a strenuous hike. The trail is easy to follow however, as of May 2015 there is quite of bit of snow still on the mountain. This Trail is nothing but inclined switchbacks gaining in elevation. Gorgeous views as you make it up the mountain to the camp area where it opens up. B/c of the snow much of the trail was lost and we had to make our way on our own. Probably best to do this during the summer when you can follow the trail more easily! Coming down the mountain was a breeze.

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