Lake Auseilla from the Tech Dam

Pretty lakes at the bottom of a little-visited cirque (altitude 2,192 m) in the pretty valley of the Ruisseau de Labas.
Marmots, chamois and vultures are often seen in the Bouleste valley.
Please note: in spring, when the snow melts, it is sometimes impossible to cross the Ruisseau de Labas at the WPT (3).

Details

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  • Walking
    Activity: Walking
  • ↔
    Distance: 13.46 km
  • ◔
    Average duration: 6h 45 
  • ▲
    Difficulty: Moderate

  • ⚐
    Back to start: Yes
  • ↗
    Ascent: + 1,006 m
  • ↘
    Descent: - 1,006 m

  • ▲
    Highest point: 2,221 m
  • ▼
    Lowest point: 1,214 m

Photos

Description of the walk

(S/E) Start from the first car park on the right when you arrive at Lac du Tech (towards Lac Uzious).
Take the path heading due west, which immediately climbs towards the forest. After 150 metres, the path passes under a high-voltage power line. Continue along this well-marked path, which eventually leads to the "estives de Mauba".

(1) The path heads north-west and, at an altitude of 1,480 m, continues due west. Follow this path and leave a water intake below on your left. Continue climbing a few steep slopes in the mountain pastures, heading due west.

(2) You will arrive at the "Cabane de Bouleste". Continue due west, crossing a stream, and leave the path on the left, which you will take on the way back. The path remains on the hillside, climbing gently. Stay on the left bank of the Ruisseau de Labas. The path curves to the left, still following the stream.

(3) Cross the stream and head southwest. The path climbs steeply, now staying on the right bank of the stream. At an altitude of 2,027 metres, the path curves to the left and continues to climb due south.
Stay on the right bank of the stream, continuing to climb along a path marked with cairns and very well marked in the scree.

(4) Stay on this path, which leads above the "Lacs d'Ausseilla" (elevation 2192). To explore the lakes in this area, you will need to cross the stream. Take note of this area so that you can easily find your way back.
This is the perfect place to stop for a snack.
The return journey will be along the same path to the "Cabane de Bouleste".

(2) From the hut, leave the path you took this morning and head to the right of the hut to descend towards the "Ruisseau de Labas" stream. You will soon see the footbridge (7).
The path you need to follow is below and parallel to the path you took on the way up.

(5) Cross this stream and continue eastwards through the rhododendrons and heather. You will need to cross the stream twice more, continuing eastwards through the mountain pastures.

(6) Continue eastwards, staying between the "Ruisseau de Labas" and the small stream "Sources des Artigues". The more or less marked path continues to descend eastwards. There is no risk, as it is a mountain pasture.

(7) Cross a footbridge and continue eastwards. You will arrive just above a track.

(8) Join this track and descend via the path that branches off to the right into the forest. Very quickly, leave the track that continues flat on your right. The path is very well marked and descends rapidly into the forest. You will come out onto a mountain pasture and continue descending to join a very stony track.

(9) Leave the path marked "Lac de Pouey-Laun". Continue on the track that turns left and heads north-east.

(10) The track leads you to the road after two hairpin bends. Turn left and follow the road for 400 metres to reach your car (S/E).

Waypoints

  1. S/E : km 0 - alt. 1,215 m - Parking - Lac du Tech
  2. 1 : km 1.38 - alt. 1,474 m - Altitude: 1,480 m. West-facing
  3. 2 : km 3.38 - alt. 1,724 m - Cabane de Boulest
  4. 3 : km 5.07 - alt. 1,892 m - Cross the stream
  5. 4 : km 6.3 - alt. 2,196 m - Lacs d'Ausseilla
  6. 5 : km 10.04 - alt. 1,693 m - Cross the stream
  7. 6 : km 10.57 - alt. 1,625 m - Location between the two streams
  8. 7 : km 11.21 - alt. 1,530 m - Cross the footbridge
  9. 8 : km 11.55 - alt. 1,501 m - Track
  10. 9 : km 12.35 - alt. 1,361 m - Track
  11. 10 : km 13.15 - alt. 1,217 m - Route - Lac du Tech
  12. S/E : km 13.46 - alt. 1,215 m - Parking - Lac du Tech

Notes

This hike is accessible, but there is a steep climb at the end.
The end of the route must be clearly marked to facilitate the return journey in case of a change in the weather.

To my knowledge, there are no water sources along the way.
We are in the high mountains, where the weather can change very quickly. You will therefore need clothing to protect you from the rain and cold. 2 litres of water, a snack for lunch, a digital camera, a 1:25,000 map, the .gpx track and the PDF of the hike.

Worth a visit

In Arrens-Marsous, there is accommodation (stopover lodge, inns, campsites), various activities, restaurants and shops selling regional products.

Reviews and comments

4.7 / 5
Based on 19 reviews

Reliability of the description
4.7 / 5
Ease of following the route
4.6 / 5
Route interest
4.7 / 5
User 591843

Overall rating : 4.7 / 5

Date of your route : Oct 18, 2025
Reliability of the description : ★★★★★ Very good
Ease of following the route : ★★★★☆ Good
Route interest : ★★★★★ Very good
Very busy route : No

A very beautiful hike. The route is perfectly marked, so it's impossible to get lost! I had a little trouble finding the trail back from the Bouleste hut, but by following the GPX track, I eventually found it again.
Difficulty level: for an experienced hiker, nothing insurmountable, although the last kilometre is quite strenuous.
The beauty of the place makes it worth the effort. Two small turquoise lakes, lost in the vastness... Magnificent!
I hardly saw anyone.
Dogs are allowed

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phil642
phil642

Overall rating : 4.3 / 5

Date of your route : Sep 29, 2025
Reliability of the description : ★★★★☆ Good
Ease of following the route : ★★★★☆ Good
Route interest : ★★★★★ Very good
Very busy route : No

A beautiful route in a wild and uncrowded area

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User 26506859
• Edited:

Overall rating : 4 / 5

Date of your route : Jul 17, 2025
Reliability of the description : Not used / Not applicable
Ease of following the route : Not used / Not applicable
Route interest : ★★★★☆ Good
Very busy route : Yes

As already mentioned, the last section is quite difficult and requires good physical condition. It is not recommended for people who are prone to vertigo or children.
The descent is complicated in wet weather, with alternating slippery earth and stones.

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Jean-Y
Jean-Y

Overall rating : 4.7 / 5

Date of your route : Jul 16, 2025
Reliability of the description : ★★★★★ Very good
Ease of following the route : ★★★★☆ Good
Route interest : ★★★★★ Very good
Very busy route : No

Very pretty little lakes well hidden in the mountains. Please note: the first lake and the upper lake are almost touching, so there's no need to look any further up.

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CMO
CMO

Overall rating : 5 / 5

Date of your route : Sep 09, 2023
Reliability of the description : ★★★★★ Very good
Ease of following the route : ★★★★★ Very good
Route interest : ★★★★★ Very good
Very busy route : No

A magnificent hike with no one else around.
The trail is beautiful and very easy to follow, but I think that after a big storm or when the snow melts, the stream must be very difficult to cross...and it's a must.
A must for lovers of solitude 👍

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taillon65
taillon65

Overall rating : 5 / 5

Date of your route : Aug 21, 2023
Reliability of the description : ★★★★★ Very good
Ease of following the route : ★★★★★ Very good
Route interest : ★★★★★ Very good
Very busy route : No

A great discovery in this valley, a beautiful hike with a fairly steep climb at the end to reach the cirque and its lakes...

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Amorgin
Amorgin

Overall rating : 4.7 / 5

Date of your route : Oct 16, 2021
Reliability of the description : ★★★★☆ Good
Ease of following the route : ★★★★★ Very good
Route interest : ★★★★★ Very good
Very busy route : No

A magnificent hike, but you need to be in good shape because it's a steep climb at the start in the woods and at the end up to the lake. Without going as far as to say it's really difficult, I'd say it's a medium+ hike. Six hours in total for about fifteen kilometres according to my GPS.

The description is good except for point 1, where it lacks precision. For example, when the author writes "leave a water intake below on the left", he could have specified "cross the water intake, leaving it below on the left" (this avoids continuing straight ahead on the path or on the one to the right...). Otherwise, the route is very precise.

In my opinion, the return trip to the right of the cabin is really worth it. There is a magnificent waterfall just 200 metres below where I took a memorable break. Otherwise, there are very few people on the trail.

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Thierry Bonnal
Thierry Bonnal

Overall rating : 5 / 5

Date of your route : Jul 23, 2021
Reliability of the description : ★★★★★ Very good
Ease of following the route : ★★★★★ Very good
Route interest : ★★★★★ Very good
Very busy route : No

A beautiful hike with a refreshing breeze, as it was 19°C in the plains at 7am and 34°C in the afternoon. Not knowing how long it would take, we didn't bring much with us (unfortunately). It actually took us 2½ hours to climb up and 2 hours to climb down. The start was quite steep, which warmed up our calves. The Mauba mountain pastures along the Labas stream were covered with various flowers, including entire "fields" of beautiful wild lilies. Many marmots watched us. At the fork to the left, the final climb seemed very steep, but in fact it was very easy to navigate via a well-marked, easily passable path. Just before we reach the lakes, a herd of izards spots us and flees. I leave my brother at the lakes to fish, but he doesn't catch much because the wind is creating ripples on the water. I climb up the steep slopes because the izards have moved higher up. And that's when I regret not bringing my 150-600 zoom lens. So I have to climb almost on all fours along the rocks so as not to be spotted. Hidden behind a fairly large rock, I can observe and photograph a herd of more than 60 izards. A magical moment. The return trip will be via the descent on the left. My GPS track shows almost 14.5 km. The time indicated seems excessive to me, as it took us 5½ hours there and back, taking the time to take photos. NB: my brother lost his beret on the descent between the footbridge over the stream and the junction leading to Lake Pouey-Laun. Happy hiking, everyone. Adishatz

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jean tango
jean tango

Overall rating : 4.7 / 5

Date of your route : Jul 07, 2021
Reliability of the description : ★★★★★ Very good
Ease of following the route : ★★★★★ Very good
Route interest : ★★★★☆ Good
Very busy route : No

A superb hike in the sunshine on Friday, 2 July 2021. We even went for a swim in the lake!

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SEMMEZIZS
SEMMEZIZS

Overall rating : 4 / 5

Date of your route : Jul 02, 2021
Reliability of the description : ★★★★☆ Good
Ease of following the route : ★★★★☆ Good
Route interest : ★★★★☆ Good
Very busy route : No

Very pretty valley - Wild - Flowery - inhabited by marmots and we saw a herd of chamois.
Follow the trail - obvious path - crossing the stream can be difficult very early in the season or after a storm.
No snow at this time of year.
This route requires a minimum level of fitness - 1,100 m elevation gain - Total time for round trip: 8 hours

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Youri_31
Youri_31

Overall rating : 5 / 5

Date of your route : Aug 14, 2020
Reliability of the description : Not used / Not applicable
Ease of following the route : ★★★★★ Very good
Route interest : ★★★★★ Very good
Very busy route : No

A magnificent hike with my son, setting off at 5am to catch the sunrise. We followed the GPS track as it wasn't easy to find our way in the dark. A few light showers around 6:30 a.m. and the sun struggled to break through the clouds. We arrived at the lake at 9 a.m., brrr. Seeing the chamois (more than 25) was the highlight of this hike, not to mention the marmots that dotted the way back.
Recommended return route as on the trail on the right, very nice and interesting because there were people at the first summer pasture seen during the descent at lunchtime, a few groups on the way up but no one at 5 a.m. ... cool.

NB: My GPS (Two Nav Anima) shows - with overlapping tracks - 16.92 km vs 13.02... and 1268 m of elevation gain vs 1132 m. 8 hours in total, including a 1-hour break by the lake.

Enjoy the hike.

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LaPierre
LaPierre

Overall rating : 4.7 / 5

Date of your route : Jul 09, 2020
Reliability of the description : ★★★★★ Very good
Ease of following the route : ★★★★☆ Good
Route interest : ★★★★★ Very good
Very busy route : No

This small lake with turquoise waters is well worth the walk!
The landscape is splendid as soon as you reach the first mountain pasture.
The place seems strangely uncrowded (we were alone at the lake, which was brilliant!). However, it's best to forget about swimming, as the water is freezing cold!
On the way down, on the left-hand side, there are lots of marmots, looking very plump at this time of year.
From the Bouleste hut, we took the indicated alternative route on the right bank. I think this descent is nicer than the other bank because it's in the woods.

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sakura69
sakura69

Overall rating : 4.7 / 5

Date of your route : Sep 29, 2019
Reliability of the description : ★★★★☆ Good
Ease of following the route : ★★★★★ Very good
Route interest : ★★★★★ Very good

A beautiful hike with numerous marmots along the route.

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milpat64
milpat64

Overall rating : 4.7 / 5

Date of your route : Sep 30, 2019
Reliability of the description : ★★★★★ Very good
Ease of following the route : ★★★★★ Very good
Route interest : ★★★★☆ Good

A very pleasant hike with magnificent views along the way. No major difficulties if you are fit
Thanks to Visorando and whoever created the listing

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visorandofredo
visorandofredo

Overall rating : 5 / 5

Date of your route : Jul 26, 2019
Reliability of the description : ★★★★★ Very good
Ease of following the route : ★★★★★ Very good
Route interest : ★★★★★ Very good

A classic in the sector; a superb hike!

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