Park in the hamlet of Les Rateaux.
(S/E) From the car park, walk down the road for 30 metres and take the barely visible path on the right; only a sign informs hikers that they are entering an alpine pasture and that they are therefore likely to encounter herds (dogs must be kept on a leash).
Follow the path as it winds its way up through the mountain pasture; it is sometimes steep. The route follows the high-voltage power line. Ignore a path on the left and, below La Saussaz, join a track.
(1) Take this track, turning left. Stay on this track for 500 metres and, after a short descent, look for a path on the right.
(2) Take the path on the right (signposted Grand Perron des Encombres 2h45) which climbs up the valley to the Petit Col des Encombres at 2229m.
(3) At the pass, take the path furthest to the right, which often runs close to the ridge.
(4) Along the way, it will cross a track used for high-voltage line maintenance. Pass at the foot of a cross and reach the Col des Encombres (2,325 m).
(5) From the pass, follow the signpost indicating Lac de la Montagnette in 45 minutes, leaving the path that descends to the right into the valley. The path leading to the lake runs along the ridge or on the northern flank of the Tarentaise slope.
(7) Turn left and reach Lac de la Montagnette (2,496 m).
(6) From the lake, return to Col des Encombres via the same route.
(5) Descend via the path on the left into the valley. Join the maintenance track.
(8) Descend straight down the track for 300m and reach the end of the road.
(9) Turn right onto the grassy track towards La Saussaz, then return to the junction you took on the way up.
(1) Descend to the left along the ascent route and return to the car park (S/E).