Most of the visitors of Almagellerhuette choose the route through Zwischenbergpass and SSE ridge. The route over Rottal to Triftgrat (SW ridge) is a bit longer and has one tricky place, but it is much less frequented.
The first part until the foot of Triftgrat is marked by yellow marks. However, they are hard to find when you start in the dark - it's a good idea to have a look the day before. The path goes first around the SW end of Dri Horlini and then continues through scree and rock field Rottal up to a platform ascending to the ridge.
It is possible to climb onto the ridge right at the start of the platform (the route is fitted with bolts). According to the guide (1993 edition) the default route ascends the platform over remains of steepening snow field which has about 45 degrees at the top. There's a rock section (II-III) between the snow field and the ridge. We had an experienced climber with us who placed a fixed rope over this section.
The route on the ridge first leads over an elevation (3820) and then joins with the normal route from Hohsaas and ascends to the peak. The ridge near the elevation was relatively steep and icy, except for that there were no problems. We descended by a normal route to Hohsaas .
This is a route nr. 798 in the SAC guide "Walliser Alpen 5: Vom Strahlhorn zum Simplon" (1993 edition).