Lake Gignoux

Lake Gignoux sits at 2,329 metres on the south-facing slope of the Cerveyrette valley, within the commune of Cervières in the Hautes-Alpes department, part of the Briançonnais area of the French Alps. It lies just east of the Chenaillet summit (2,650 m), close to the ridge that marks the border with Italy, and is one of several small alpine lakes reached on foot from the village of Cervières.

How big is the lake and what does it look like?

Lake Gignoux covers roughly 1.9 hectares, set among scree slopes and moraine in a stark, mineral landscape typical of this part of the Alps. Locals and hikers sometimes call it the "lake of seven colours," a nickname tied to how its surface shifts between deep blue and pale green depending on light, depth and time of day. That shifting palette, more pronounced here than at many neighbouring tarns, is a large part of the lake's draw for hikers and photographers.

What peaks and other lakes surround it?

The ridgeline north of the lake forms part of the French-Italian border. Visible from the shore are Cime de Saurel (2,449 m), Grand Charvia (2,648 m) and Pic de Peyre Eyraute (2,903 m), while the nearby Col de Gimont provides a link toward the Susa valley on the Italian side. A short stretch along the approach trail passes Lac Noir (2,226 m), a smaller lake often visited on the same outing.

Why does the geology here stand out?

The rock around Lake Gignoux includes basalt and gabbro outcrops exposed among the scree and moraine — remnants of ancient oceanic crust. Geologists trace these formations to the Liguro-Piedmont Ocean, part of the wider Tethys Ocean roughly 150 million years ago, when the seabed here lay some 3,000 metres deep. For visitors with an interest in Alpine geology, the lake basin offers a rare, accessible cross-section of that deep past.

What plants and animals live around the lake?

The area is recognised as a protected natural site. It supports around a dozen rare plant species, two of them under national protection, adapted to the subalpine and alpine belts that surround the lake. Wildlife recorded in the vicinity includes red deer, rock partridge, black grouse and the Apollo butterfly, a species often used as an indicator of well-preserved high-mountain habitat.

How do you get there and how long does the hike take?

Access is via the D89T road up the Cerveyrette valley from Cervières, with parking near the old La Chau farms at around 1,893 m. From there, the trail passes the Sainte-Elisabeth chapel toward the Fraches sheepfold before climbing to the lake. The direct round trip takes about 2 hours 45 minutes with roughly 450 m of elevation gain. A longer, popular loop links Lake Gignoux with Lac Noir and Lac des Sarailles — about 10 km and 500–650 m of climbing, taking 4 to 5 hours. The route is considered suitable for families but is poorly marked in places, so carrying a map or GPS track is worthwhile. Unlike the busier north-facing slopes nearby, this side of the valley is dry and has no ski infrastructure.

FAQ

How long does it take to reach Lake Gignoux? From the La Chau parking area, the round trip is about 2 hours 45 minutes, gaining roughly 450 metres in elevation.

Is the trail difficult? No — it's rated a family hike, though some sections are poorly marked, so a map or GPS track helps.

Can the visit be combined with other lakes? Yes. A popular loop connects Lac des Sarailles, Lake Gignoux and Lac Noir over about 10 km and 4 to 5 hours.

Why is it called the "lake of seven colours"? Because its water shifts between shades of blue and green depending on depth, light and time of day.

Is there any ski infrastructure nearby? No. The south-facing slope of the Cerveyrette valley is dry and undeveloped for skiing, unlike the north-facing slopes in the area.