Today I found some old GPS tracks from my journey, and managed to identify the place. It is the Urdbøurdi Scree at Arabygdi (see http://en.hardangervidda.com/Hardangervidda-National-Park/Amazing-Geographical-Features/The-Urdboeuri-Scree-Arabygdi)
“There is an enormous scree formation across the valley at the west end of the Totak lake. The Urdbøuri scree is probably the largest in Northern Europe.”
Visit Norway identifies it as the Gloppedalsura scree:
Gloppedalsura consists of avalanche boulders that are piled on top of an end moraine.
10,000 years ago the ice sheet that covered the area, melted away. For a period of time the massive end moraine dammed the Hunnedal river’s former course, towards Veen and Vikeså, and formed a lake in Byrkjedalsgryta. The terraces in Byrkjedal at 240 metres altitude are evidence of this moraine-dammed lake. The annual cycle of frost and expanding ice broke free a vast number of boulders and rocks and sent them tumbling down the southern mountainside. This debris settled as a 100-metre thick scree on top of the moraine.
Hunnedal river and the lake in Byrkjedalsgryta were forced to find a new outlet; the water burrowed a gully from Byrkjedal towards Gilja – Giljajuvet.
Directions: Drive from Ålgård towards FV45 Dirdal and Byrkjedal. Follow signs a couple hundred metres past Byrkjedalstunet.
Credit:stackoverflow.com‘