Thunder Lake Trail is a 11.2 mile moderately trafficked out and back trail located near Allenspark, Colorado that features a lake and is rated as difficult. The trail offers a number of activity options and is best used from March until October. Horses are also able to use this trail.

Distance: 11.2 miles Elevation Gain: 2,234 feet Route Type: Out & Back

backpacking

camping

hiking

horseback riding

nature trips

bird watching

forest

lake

river

views

waterfall

wild flowers

wildlife

bugs

rocky

snow

Reservations to enter the park will go on sale through Recreation.gov at 8 a.m. Mountain Time on Thursday, May 28. Reservations will be available to enter the park from June 4 through July 31. The next release will be on July 1, for the month of August and any remaining days that have not been booked for July. On August 1, reservations will be available for the month of September and any remaining days that have not been booked for August. On September 1, reservations will be available for the month of October and any remaining days in September that have not been booked. Permits issued using the reservation system will allow park visitors to enter the park within two-hour windows of availability between 6 a.m. through 5 p.m. This process will facilitate advance payment of entrance fees, minimize contact between park entrance station staff and visitors and limit congestion in parking lots. The permit system will apply to all areas of the park. In the initial opening phase, the park will open approximately 60 percent of the park’s maximum parking capacity or 4,800 vehicles (13,500 visitors) per day. Thunder Lake (10,574') is a popular destination in the Wild Basin. Begin your journey on the well marked trail at the Wild Basin trail-head. After about 1.5 miles, you'll encounter a junction: left to Ouzel Falls and Calypso Cascades or right on the Thunder Lake/Campsite trail. It is along this part that there are many back-country campsites. Horses are not allowed on this segment of the trail. An occasionally steep ascent brings you after another 1.3 miles to a junction with the Wild Basin Trail that went via Ouzel Falls. A gradual ascent on the well-maintained Thunder Lake Trail for another 2.8 miles past that junction will get you to the Lake. You'll be rewarded with views of the Continental Divide, Boulder-Grand Pass, Tanima Peak, Pilot Mountain, and the massive Mount Alice. You'll need a park pass, or pay an entrance fee.

hiking
7 months ago

Hiked 10/12/19. Was a beautiful day with a decent amount of ice/snow on the trail, mainly turned slush by afternoon. Was a pretty intensely windy at the lake, even saw some white caps, so didn’t stay long, but views were beautiful. The lake was just starting to freeze at the edges. I made this a partial loop, taking the trail past Calypso Cascades & Ouzel Falls on the way up (adds about 1 mile to the total trip). Most of the people dropped off after the falls & didn’t see anyone else while at the lake on the trail back past the campsites. Would likely recommend traction (micro spikes or crampons) at this point in the season. Enjoy it!

hiking
7 months ago

Bowl hikes are few and far between... many want summits or waterfalls. But these views are fantastic -- edge of lake staring straight up. Long hike, but not too tough and you leave all the tourists behind down at Ouzel. Wild Basin is a special place once you get past the 4-5 mile marker.

hiking
7 months ago

Well maintained trail thunder lake is beautiful well worth the hike

hiking
8 months ago

Great hike, really the distance is the biggest challenge. I agree with the others, hit Ouzel Falls on the way down, it's worth it. Snow free as of this writing.

hiking
8 months ago

I am originally from New York and was traveling to Colorado. I wanted to hike a gorgeous trial in the Rocky Mountains and was recommended this one. After looking at the reviews, I relied especially heavily on the one before mine by Clayton, and I am glad I did. If you plan on hiking this trail, read his review!! I will only add that I am NOT from Colorado, I am not thin not fat, and in meh shape, (I do hike quite a bit though) and the hike was HARD. We were on a time limit and pushed ourselves to the max, but even without that, if you are not used to the altitude or elevation, it is a real thing. Bring a ton of water, a sweater, and take breaks. The trail is very well maintained, and on 9.16.19 there was no snow, no mud, and bugs pretty much left us alone. We saw deer, ground squirrels, chipmunks, squirrels, gorgeous birds, and moose. The view when you finally get to the lake is splendid. It really is.

hiking
9 months ago

Using the most direct route (the backcountry campsite access trail), this is a steady and not overwhelming climb to Thunder Lake. Its difficulty is mostly length as it never felt like a physical challenge at the pace of our party (two Denverites and one foothills resident). Unlike the Wild Basin Trail, the route is pretty monotonous until it reaches Thunder Lake. Get ready for mile after mile of lodgepole regrowth from the Ouzel Fire and some older (and sicker) stands with North St. Vrain Creek roaring far below. On the flip side, that meant a very quiet trek with relatively fewer hikers than many other Wild Basin and most other Rocky Mountain NP trails. I would definitely recommend using the Wild Basin Trail to make this a figure-six, whether on the way up or way back. This adds about a mile to your trip and is much busier with families trekking to Calypso Cascades. However, the waterfalls of Ouzel Creek are worth the price. Thunder Lake itself is striking, large, and obviously deep. It sits in a very dramatic setting at and just above timberline. Rising above are a series of 12ers, 13ers, perennial snowfields and Boulder-Grand Pass. Conditions this weekend were generally good but extremely gusty winds in the Thunder Lake basin dissuaded our party from attempting Lake of Many Winds and Boulder-Grand Pass. Will definitely be back for another attempt before the end of the season.

hiking
10 months ago

Thunder Lake is a phenomenal hike! The trail is beautifully maintained and as of 7/23/19 there are no snow piles on or squishy parts of the trail. There are plenty of snow banks around the lake. Everything is green! If you hit the trail early you’ll have it to yourself.

hiking
10 months ago

100% clear of snow on the trail and all campsites. There is still just a little bit of snow on the banks of the lake. And the lake edges are a mud pit. Amazing hike though!

hiking
10 months ago

Had a great hike today. Wildflowers are great for the lower half of the hike. While there is a lot of snow at the lake, there wasn't any before the last half mile or so, and it didn't cause any problems. Between the snow and the marshy conditions, there wasn't really any good place to sit by the lake. That should change in the next week or two. Very few people on the trail.

hiking
10 months ago

Snow was not an issue as it was easily passable. However, the lake is surrounded by snow and a lot of run off. I could not make it around as I have in the past. Saw deer and moose. Most definitely worth it.

hiking
muddy
snow
11 months ago

What Karen said... it’s a hike through snow the last mile or so; campsites under snow, but beautiful. Hiked in on 6/30 and out on 7/1. If I can do it, you can.

hiking
muddy
rocky
snow
11 months ago

Hiked up to Thunder on 6/28, stayed one night and came down 6/29. Beautiful with all the record snow run off! Last mile still has 3-5 foot drifts with slippery snow. Recommend spikes but some post holes inevitable. Thunder mostly clear but still frozen around the shoreline. Breathtaking views! We kept saying we’d like to come back in the summer, but it is summer! Do take the campground cutoff going up, but try the Ouzel Falls way going down. Loved this trail and love RMNP. Go early to park!!

hiking
11 months ago

hiked 6/28/19. so beautiful!! trail is covered in snow ~1.25 miles from the lake. microspikes helpful, but not necessary. trail was well marked, and the crowds thinned out after ouzel falls.

hiking
muddy
off trail
rocky
snow
11 months ago

Camped at the Siskin campsite then day hiked to the lake the next day. Just so happened to snow the night before and we were hiking in 4-5 foot snow drifts. It was definitely challenging and hard to find the trail at times. We had crampons, but snow shoes would have made it easier. The views from the lake were worth it and I would like to come back when its a bit warmer.

hiking
snow
11 months ago

Hiked 6/20/19: most of the trail was clear and just wet. There is still a lot of snow in the last 1 to 1.5 miles. Recommend bringing crampons or snow shoes and hiking poles. Go early and watch for quick changes in the weather. Got caught in a couple of rainstorms and would have benefited from some all weather gloves and rain pants. I thought the views and the lake were worth it. A lot of water at the falls and along the way. Also very beautiful.

muddy
snow
11 months ago

wicked walk. the snow pack is still deep the last couple miles but soft in spots. I broke 1 trek pole and bent another. worth it to story out of the creek! the water at the basin is insane this season. go have fun but be always be mindful.

hiking
Mon Jul 30 2018

While Thunder Lake itself is a serene beautiful spot, getting there isn't that much fun. Tons of loose rocks underfoot and not a flower in sight makes this a boring trail. Didn't really enjoy much after Ouzel Falls to be frank.

hiking
Mon Jul 09 2018

Beautiful lake!

Sun Jul 08 2018

Beautiful hike along the river! Not crazy busy which was nice. Large waterfall about 1.5 miles in that you can hike directly up to off to the side. The lake is stunning, but don’t plan on swimming without a wet suit. More like 14 miles round trip...mild elevation gain which made it totally doable. Have a rad hike!

hiking
Sat Jul 07 2018

I would rate this trail as easy-moderate, not hard. It was only a little rocky and steep in a couple of places through the backcountry sites. The rest was flat or gradual incline. Two hours up, 1.5 hours down. It's more like 12 miles RT as opposed to 11 miles. The trail through the forest was quiet and beautiful. I started at 7:30 AM and saw almost no other people until I was coming down the trail. I had the lake completely to myself for the entire hour and a half that I sat there. Definitely take the route shown on AllTrails (through the backcountry sites)--it cuts a mile off each way (as opposed to going past Calypso Cascades and Ouzel Falls, unless you want to see those!) so that it's 12 miles RT instead of 14.

Wed Jul 04 2018

great camping, and a challenging hike!

backpacking
Mon May 28 2018

We did a two nighter out to Thunder Lake and it was worth the journey to see the lake! The hike up most of the way is easy going but can get very rocky in spots, especially between the Pine And St Vrain camp spots. Once we were about 1.5 miles out there were pretty huge snow mounds dotting the trail and once you get to a bridge the trail completely is lost to the snow. It was pretty easy to post hole out there too. There were quite a few tracks but none of them were the same as our map or gps. Once you get there it is quite the view and super quiet.

Fri Dec 15 2017

Done this hike twice now. Very worth it.

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