Nestled above the villages of Passy and Servoz, the lac de pormenaz glistens like a sapphire set in a bowl of granite. The lake lies at the foot of the pointe noire de pormenaz and is fed by the gentle rush of the Souay torrent, offering a spectacular backdrop for any trail enthusiast. As I trekked from the parking area at Plaine Joux, the ascent unfolded through alpine pastures, stone‑laced forests and the occasional ladder‑aided scramble that reminded me why this hike is a favourite among seasoned hikers and families alike.
What makes this spot truly universal is its blend of easy‑going scenery and technical challenges. In summer the meadow blooms with wildflowers, while in early autumn the golden‑brown alpages de pormenaz provide a quieter, snow‑kissed perspective. Whether you’re hunting for a peaceful picnic area, a chance to spot ibex, or just a photograph worthy of your travel blog, Lac Vert – more commonly known as Lac de Pormenaz – delivers on all fronts.
Table of Contents
Getting there: from Chamonix to the trailhead
The most convenient entry point is the passy nature reserve parking lot at Plaine Joux. From the tourist office in Passy you can collect a free map and a concise trail guide. The route to the lake is well‑signposted along the route de la côte, a winding road that offers sweeping views of the Mont Blanc massif before you even start the hike.
- By car: Take the D907 from Chamonix to Passy, then follow signs to Plaine Joux (approx. 30 km, 45 min).
- Public transport: Bus line 11 runs from Chamonix to Passy every hour; a short taxi ride will drop you off at the trailhead.
- Parking: Free parking for up to three hours; a small fee applies for longer stays.
Once you park, the start of the hike is marked by a wooden sign pointing toward the lac vert and the chalets du souay that line the lower slope. The first few hundred metres wind through a mixed forest of spruce and larch, the air scented with pine and damp earth.
The ascent: trail overview and key features
The complete loop to Lac de Pormenaz measures about 13 km and entails an elevation gain of roughly 850 m. Depending on your pace, the duration ranges from 4 hours (fast hikers) to 6 hours (families with children or those stopping often for photos). Below is a quick glance at the trail statistics:
| Metric | Value |
|---|---|
| Distance (loop) | 13 km |
| Elevation gain | 850 m |
| Maximum altitude | 2150 m |
| Difficulty | Moderate (technical sections) |
| Best season | Summer to early autumn |
From the trailhead, the first major landmark is the souay torrent, a fast‑flowing stream that you’ll cross via a set of sturdy wooden cable passages. The water is icy in June but mellows as summer progresses. After the crossing, you ascend a gentle gradient that opens onto the alpine pasture of Pormenaz, dotted with the iconic red‑roofed châtelet d’ayères. In early July, the pasture is a canvas of yellow and purple alpine flowers, while late summer brings the occasional sighting of curious wildlife such as marmots and chamois.
Technical highlights
- Scramble sections: Near the lake, a short rock scramble requires the use of the ladders installed by the local mountaineering club. The difficulty is classified as ‘easy technical’ – manageable for most hikers with a head for heights.
- Gorges de la Diosaz: A side detour leads to these dramatic limestone gorges, offering a cool shade and an impressive echo when you shout.
- Point of interest – La Chorde: A small but striking waterfall located a few minutes before the lake, perfect for a quick drink.
Points of interest and photo opportunities
The lake itself is a mirror, reflecting the peaks of the aiguilles rouges and the distant silhouette of the montagne de pormenaz. The lac vert water is a vivid turquoise thanks to alpine limestone suspended in the meltwater. Photographers will love the early morning light when the sun paints the surrounding cliffs in gold.
“As an Italian, I’ve never seen a place quite like this. After three hours of walking, the scenario is amazing. Everyone must try it.” – Visitor review (4.8 / 5)
Other notable spots include:
- Chalets du Souay: Traditional wooden houses where you can often meet local shepherds.
- Picnic area: A flat stone slab by the lake, equipped with a waste bin and a bench – ideal for a lunch break.
- Refuge: The modest refuge du Pormenaz offers simple meals and warm drinks during the cooler months.
- Wildflower meadow: Between June and early August, the meadow bursts with alpine edelweiss, gentians, and saxifrages.
Risk considerations & difficulty assessment
While the trail is popular, it is not without hazards. Here are the main safety considerations you should keep in mind:
- Weather: Alpine conditions can change rapidly. Even in summer, thunderstorms may roll in after noon. Check the weather forecast before you set out.
- Snow conditions: Early June may still see patches of lingering snow on the highest sections, especially after a late winter.
- Technical difficulty: The scramble near the lake includes exposed rock and a few steep drops. Use the installed ladders and wear sturdy hiking boots.
- Wildlife: Ibex and chamois are accustomed to humans but keep a respectful distance. Dogs are allowed on the trail, provided they are on a leash.
- Navigation: Trail markings are clear, but fog can obscure them. Carry a topographic map or a GPS device.
Seasonal tips, weather and optimal timing
The best time to visit Lac de Pormenaz is from late June to early September. During this window, the summer weather is generally mild (average highs 20‑22 °C) and the alpine flora is at its peak. For those seeking fewer crowds, early July and late August offer a pleasant balance of good weather and quieter paths.
In the shoulder season (late May and early October), you may encounter lingering snow on the higher sections and cooler temperatures near the lake. If you choose to hike during these months, bring crampons or microspikes and dress in layers.
Practical information: dogs, picnic, and amenities
Dogs are welcome on the trail (dogs allowed), but they must be kept on a leash to protect the fragile vegetation and to avoid startling wildlife. There are no dedicated dog stations, so bring your own water bowl.
The designated picnic area near the lake provides a clean spot for a meal. Pack out all waste – the passy nature reserve maintains a strict “Leave No Trace” policy.
If you need to replenish supplies, the village of Servoz, located 5 km downhill, offers a small grocery store and a bakery famous for its savoyard cheese croissants.
Frequent Asked Questions
Is Lac de Pormenaz suitable for families with children?
Yes, the majority of the route is a steady walk through forest and meadow. The only technical part is a short scramble near the lake, which younger children can skip by turning back at the last marked fork. Always keep an eye on kids near the water and rocky sections.
What is the total elevation gain and how does it affect the hike?
The loop gains roughly 850 m from the trailhead to the lake and back. This moderate ascent means a fit adult will take about 4 hours, while a slower pace or frequent breaks can extend the hike to 6 hours. The altitude is low enough that most people won’t feel significant effects, but the final approach to the lake is at about 2150 m.
Are there any cable passages or ladders on the way?
Yes, you will cross the Souay torrent via sturdy cable passages early on, and later a short set of wooden ladders assists the scramble to the lakeshore. Both are well‑maintained by local volunteers.
Can I see wildlife such as ibex or marmots?
During the summer months, ibex often graze near the alpine pastures, and marmots are heard chirping from the higher cliffs. Keep a respectful distance and use binoculars for close observation.
What should I pack for a summer hike to Lac de Pormenaz?
Essentials include a waterproof jacket, layered clothing, sturdy hiking boots, a hat, sunscreen, a 2‑liter water bottle, snacks, a map or GPS, and optionally trekking poles for added stability on uneven terrain.
Beyond the lake: extending your alpine adventure
If you’ve finished the loop and still have energy, consider heading toward the pointe noire de pormenaz for a brief summit walk. The view spans the Mont Blanc range, the aiguilles rouges**, and the glacial valleys below – a perfect reward for the extra effort.
Another option is the Tour des Fiz circuit, a longer trek that links several high‑altitude lakes and passes through the gorges de la diosaz**. This route adds roughly 6 km and a further 300 m of ascent, making it suitable for experienced hikers looking for a full‑day challenge.
Final thoughts on Lac de Pormenaz
In short, Lac de Pormenaz offers a superb blend of natural beauty, moderate challenge, and practical accessibility. Whether you’re a seasoned trekker hunting the next breathtaking point of interest, a family seeking a day‑out in the haute-savoie mountains, or a photographer after that perfect turquoise lake shot, this destination checks every box. Remember to respect the environment, check the weather, and enjoy the ever‑changing alpine palette – the lake will be there, waiting to reflect your next adventure.
