Start: From Chamonix, head for Col de Forclaz on the D1502. After Le Lavancher, at a traffic circle, go straight on, in the direction of the cable cars, and park a few 100 m further on, in a car park which is parallel to the road, on the left as you go up, at a place called La Rosière.
(S/E) Take the paved La Rosière path up through the chalets of the hamlet of La Rosière. Continue until you reach the edge of a wood and a crossroads.
(1) At the crossroads, take the path on the left, signposted "la crèmerie du glacier". Pass under the Plan Joran chairlift, then the Lognan cable car, until you reach a bridge.
(2) A few metres before this bridge, pass the ski slope and take the path on the right, to climb the slope that passes over the bridge. Reach the ski run and follow it to the right. Climb steeply straight ahead. As you climb, the panorama of the valley becomes increasingly magnificent. The gradient is steep on this first section. Keep going. Just before a ford, you'll come to a signpost for the Refuge de Lognan.
(3) Take the path that climbs to the left through the woods towards the Refuge de Lognan. As you leave the wide track, you'll have a view of the La Croix de Lognan lift station. Continue up the steeply ascending path to the refuge. From the refuge, you can see the beginnings of the glacier.
(4) From the hut, take the small path that heads off in the opposite direction through the vegetation to join the wide track as far as an intersection. If you want to see the foot of the glacier, continue left to a shed and a hydro-electric tunnel.
Retrace your steps and take the left-hand track that climbs along the glacier to reach the first glacier lookout.
(5) From this point, the trail climbs to a ridge along the glacier, not shown on the IGN map. Quite a technical passage__, requiring sure footedness, across a scree. Continue to a metal post on a large boulder, marking the end of the trail. At the foot of the boulder, a sign reads "Point de vue 2230m alt". The view and panorama over the glacier are extraordinary, with the Aiguilles du Chardonnet and de l'Argentière to the east, and the Aiguille Verte and Les Drus to the west...
(6)The return journey begins on the wide path below the one you took to go up, until you reach a junction (a track that leads you to the first lookout point on the glacier). This part is slippery due to the stones that cover it.
(7) Turn left along this path, which leads to a very wide piste (a ski slope in winter), and continue to the Croix de Lognan lift station. From here you can see the Grands Montets peaks and its cable car (in maintenance when we did this hike in August 2019). Follow the trail to the Tabé chairlift and its high-altitude restaurant.
(8) Turn right onto the track that descends for a few metres to the start of the Tabé chairlift, then turn left onto a path (signposted "sentier piéton") that winds steeply down into the Bois des Chosalets.
(9) At the intersection, turn right and take the long, winding descent.
(10) Exit onto a path and follow it to the right.
(1) At the crossroads, turn left. Cross the hamlet of La Rosière to find the car park (S/E).