Access

From Aosta take the Gd St Bernard road until about 2kms beyond the service station at St Rhemy en Bosses. Take a turn off on the right to the Mottes ski area. Park the car at the foot of the chairlift.  

Routecirca 2.5h

Pass under the hairpin of the Gd St Bernard tunnel road and go in the direction of Le Ponty by the alpine road to reach Arp Bois 1940m.  (It is possible to take a shortcut by going up to the left shortly having crossed the first bridge and then traversing diagonally upwards throught the larch forest to rejoin the road before the buildings.) Just before you reach the lower of the two groups of buildings go SW to the obvious cwm that leads to the col (or fenêtre) de Sereina.

Variant 1: circa 3.5h
N.B. To the right of the cwm is the NE face coming down from the crête de Sereina, (2744m).  This gives several ascent/descent options, depending on snow conditions, which are best reached from the higher group of buildings.
Variant 2:
From the col de Sereina (2547m), you can reach the NW summit (2710m) by its S face (35° gully).  This summit gives access to ski down a cwm steeper than that of the cwm leading to the col.

Descent

By the ascent route.  

At the beginning of the season the valley is fairly austere,(faces NE.)  Higher up, through the larch trees, is more pleasant.