Thunder Lake Trail

HARD 32 reviews
#69 of 191 trails in

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.

11.2 miles
2,234 feet
Out & Back




horseback riding

nature trips


bird watching






wild flowers





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 2.7 miles, you'll encounter a junction: left to Bluebird Lake, right to Thunder Lake. It is in this area, on the north side of the trail that there are many back-country camp sites. A gradual ascent on the well-maintained Bluebird Lake Trail for another 3.6 miles past the 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.

6 months ago

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.

7 months ago

Beautiful lake!

7 months ago

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!

7 months ago

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.

7 months ago

great camping, and a challenging hike!

8 months ago

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.

Friday, December 15, 2017

Done this hike twice now. Very worth it.

Wednesday, October 25, 2017

Great hike, trail clear of snow for the most part. GPS watch had it at ~ 13.4 miles rather then the 11.5 listed.

Friday, September 29, 2017

Lots of up after you cross the bridge after it splits off from Ouzel Lake trail, which I only saw 5 people from that point on. Still plenty of trees with a couple good spots that open up to give a good panoramic view. The trail was wet and muddy in spots with puddles in areas. Some ice and snow from the storm the day before, a lot of it melted, but there were still remnants when I was heading back down. When you get close you actually descend to get to the lake. I found a trail that I followed half way around the lake, great for different views of the area.

Sunday, July 09, 2017

Beautiful hike! My pal and I had a small picnic at the lake and it was so much fun! However, our fit bits recorded a much farther hike than 11.5 miles (~13) but we did explore around the lake some too.

Monday, July 03, 2017

Beautiful hike, saw two moose (mother and calf) near Copeland Falls.

Wednesday, June 28, 2017

This was an amazing hike! It's very rocky in some areas, and is quite a long hike, but worth every step. The view is incredible. There is still a lot of snow up there, so be sure to wear boots. The trail gets lost under the snow, so follow the footprints. The ranger station is no longer under snow, but there is nobody stationed there yet. Our 10 year old daughter did this with us, and although it's challenging, it definitely doable!

Thursday, June 15, 2017

We did a one nighter last weekend. Still lots of snow but packed. Lake was about 80-90% frozen that made it easy to pump water. GPS was helpful to help us get to the lake and not waste time guessing since the trail was 100% covered in snow and NO TRAIL MARKERS noted on trees as guidance. Ranger station was buried halfway in snow. We saw two guys up there but they were day hikers. We had the lake to ourselves. We camped in snow. If you're not keen on doing that maybe another month or so would be best. Two ways to get up there. The trail splits at the sign where it reads No Llamas. To the right. This is the split that's shorter to get to Thunder lake by almost a mile but it's wet and rocky. This is less used by day hikers in general. If you choose to take the other trail it is longer and undulating and as you go higher is covered in snow but dry to Ouzel Falls.

Sunday, June 04, 2017

Didn't go all the way. Deep snow but packed providing a good workout. Would recommend crampons for traction. Again good workout with snow but we didn't really care if we made it to the lake.

Monday, September 26, 2016

This is a really long one (at least for me) but it wasn't super difficult. The elevation gain is mostly gradual and there's several cool things to see along the way. I started at 8:30 and got back to the trailhead at 2:00, so it'll take a good chunk of the day to do, but really great mountain and lake views at the end. I think Sky Pond, Mills, Haiyaha, and Emerald lakes have a better view at the end for less effort, but I'm glad I did this one; it was fun.

Wednesday, August 10, 2016

SO BEAUTIFUL, the trail is very long and ALL up hill on the way to the lake but once you're there, it's worth it. The lake is surrounded by big mountains and its not crowded due to its difficulty to reach. Good place for lunch. The walk there was very scenic, lots of pines and then sections with different things to see and flowers. You cross 2 amazing waterfalls also. Way back is easy, all down hill

Monday, August 08, 2016

This hike is NOT hard! And boring? What?! From the trailhead, there's Coleman Falls, Calypso Cascades, and Ouzel Falls. There is a break here until Thunder Lake is reached, but along the way are fascinating things if you stop to look. Through the trees, peaks pop into view. The St. Vrain is your constant companion, dipping under bridges and gurgling alongside. Meadows break out where deer and moose wander. Interesting boulders form instant shelter from rain. Never a dull moment. It wasn't very crowded after Ouzel Falls. Take the side trail to the top of Ouzel Falls. It's well worth it. All six of us agreed this one is easy with moderate on occasion. Fantastic, but long, hike!

Monday, September 08, 2014

I have done this trail as a day hike and backpacking. I love it as a day hike. It's a pretty easy overnight backpacking trip--exceptional for outta town friends who may not be acclimated to the altitude. The forests are beautiful the last 2 or so miles towards Thunder Lake. Typically a lot of traffic. I enjoyed it.

Monday, September 01, 2014

This was my third time to Wild Basin- one failed attempt at Sandbeach Lake due to snow, and one failed trip to Ouzel Lake due to the bridge being out since May, 2013 (we just went to Ouzel Falls instead).

Thunder Lake itself is a rewarding destination, framed by Tanima Peak and Boulder-Grand Pass (which does offer dramatic views, as another reviewer said!). The backdrop of the mountain is so close and abrupt that it kind of surprised me! Pictures do not do it justice. Wildflowers dotted the landscape all the way to the west side of the lake, along the trail. While I am so happy to have hiked here, the reason for the three stars is that it was... kind of boring to get to.

The St. Vrain creek was so enjoyable to walk next to, and the valley was pretty, but you are mostly in the trees, especially once you get to the primitive campsite spur trail. However, besides the length, I didn't find the trail to Thunder Lake to be too strenuous. Yes, there were some switchbacks, but not many, and there were many flat parts of the trail for resting.

Again, I did very much enjoy this trail, and do not at all regret hiking it, but compared to other trails I have hiked, I gave it three stars. I would like to come back to this area in a few weeks when the aspen turn yellow.

Sunday, August 12, 2012

It's about 6.8 miles one way, about 2100' in elevation gain, with most of the gain in the second half of the hike. Difficult hike with a full pack (or without a pack), but plenty of points of interest along the way to use as rest stops.
The first half or so is on the Ouzel Lake trail, with the St Vrain river rushing next to the trail. Calypso Cascades runs underneath one of the many bridges on the trail. Ouzel Falls is a very short side hike off the main trail. The second half of the hike is all uphill on a very rocky trail.
Lake is tucked up against a mountain, making for dramatic views. The cascading river feeding the lake is on the far side.
Backcountry camp sites are about 200 yards above the lake, and require a permit and bear resistant container.

4 months ago

5 months ago

8 months ago

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