This tour up Storsteinsfjellet is a ski mountaineering endeavor - the skiing pleasure down the flat glacier is limited, but the airy ridge, steep south couloirs, immense views and the feeling of remoteness make for a rewarding outing.
The tour is done ideally when the Norddalen road is open. Drive or cycle about 18 km from the gate in Fjellbu to Vuostagorzi (690 m) at the end of road and the end of the power line. You can park there. Due the condition of the road and the remoteness, a high-clearance vehicle (ideally AWD/4x4) and spare tyre are advised.
Start the skitour by following a faint summer trail to your left (heading NE). If you come when the road is open, you may have to carry skis for some time. Continue up undulating but easy terrain until you reach the drainage of the SE glacier. Head up the drainage on the left (west) and ascend the glacier.
Skin up the flat glacier. At around 1440 m you reach a crevasse zone - the bulge and cracks are often visible. Pass that area to your left (west). Remember that spot for the descent - skiing fall-line down the glacier will lead you right the crevasses. Continue up the upper section of the glacier until you reach the col at the base of the SW ridge. When I was there, I found it easier to tackle the ridge slightly to the east of the prominent col than from the col itself, via a short snow climb. Follow the ridge to the summit, climbing over big blocks. A rope is advised here - there is real fall hazard!
To descend, climb down the ridge a few meters, and ski down the south face (to 40°). The south face may also be used as an ascent route.
Then follow your ascent route back. The skiing on the glacier itself is really mellow.
Alternatively, one can climb the SW summit (1871 m) via a short 40° snow slope. To do so, follow the route as above, but at 1650-1700 m, head west from the glacier. The summit is straight ahead of you.
These routes may be doable well into the summer months.