That white streak on the mountainside ahead is Hydnefossen, the highest waterfall in Hallingdal. The main drop is 155 metres, but the water continues tumbling down the slope for a total fall of 475 metres.
It's actually better seen from here on the road than up close. The mountain Veslehorn rises behind it at 1300 metres.
In winter, ice climbers scale the frozen cascade. In summer, hikers on the route to Veslehødn cross over the top of the falls - one of Hemsedal's most popular mountain hikes. From up there you can peer down the gap where the water disappears into the valley.