This hike is rewarding and challenging, yet very accessible. The lift system saves you time and effort, meaning that you can spend more of your day enjoying the tranquility and beauty of this remote spot.
Starting from Planpraz at Brevent, turn left out of the lift station and follow the wide path past the Altitude 2000 restaurant (closed in summer). On a good calm day you’ll see parapenters taking off from the grassy field on your left.
Continue up towards the chairlift pylons and bear right towards Flegere; after a couple of hundred metres you’ll come to a footpath on your left that climbs uphill through open fields before reaching a scree slope. Scramble across the scree (it’s not too steep or challenging) and pass through a narrow gap.
The trail becomes steeper as it approaches Col Cornu and you pass between the impressive peaks of Aiguille de Charlanon on your left and Aiguille Pourrie on your right; once you’ve reached the summit of the col at 2414m the trail drops down to the lake.
The lake itself is surrounded by rocks that make good picnic tables and the occasional grassy patch. The rocks make for quite eerie acoustics and you can often hear the cawing of birds or bleating of goats, magnified and distorted from their usual sounds. The views are spectacular and you get a completely different perspective by being on the other side of the mountain.
You can either return via the same route, or make a circuit of it by descending to Flegere and taking the cable car down to Les Praz, from where you can catch the bus back to Chamonix or walk alongside the river.
Worth knowing
You will need a lift pass to access both the Planpraz-Brevent and Flegere lifts.
Watch out for
The area around the top of the col and the descent down to the lake can quite often be covered in snow, even in quite late spring. Check weather conditions before you go and consider taking hiking poles.
Who should go
This is an excellent half-day hike for anyone with a reasonable level of fitness who wants to get away from the more well-trodden routes.
What to bring
This hike is very exposed with no shade or shelter so check the weather and be prepared with sun cream, sun glasses, hat, spare layers of clothing, etc. High altitude can bring on dehydration so make sure you have plenty to drink.
The ground is rocky (and sometimes snowy) underfoot, so wear decent hiking shoes and consider using poles.
A map is not essential as the route is signposted but it is always useful to have one for reference - the map that covers this area is IGN 3630OT.
What to see
It is common to see alpine wildlife in this area such as chamois and bouquetin. Marmots often live amongst the rocks, so keep an eye out for them once you get higher up.
Where to lunch
The Bergerie at Planpraz serves lunches, snacks and drinks throughout the summer; they have a lovely sunny terrace with great views. Lac Cornu is a great place for a picnic if you prefer to bring your own food.
