Lac de Tseuzier
Lac de Tseuzier is an artificial lake at an elevation of 1.780m (5,839ft) above the sea level, located north of Crans-Montana in the Swiss canton of Valais. There are really steep sections, up to 27%.
Located in the Bernese Alps, the road to the summit is asphalted, but pretty narrow, with sections impassable for 2 cars at the same time. Nearing the dam there are several tunnels, a couple are very long.
The road to the lake was built from 1953 to 1957. It’s pretty steep. Starting from the town of Giète, the ascent is 9.7 km long. Over this distance the elevation gain is 626 meters. The average gradient is 6.45% with some really steep sections, up to 27%. The last couple of kilometres are virtually flat mainly in tunnels. At the summit there’s a big parking lot.