Col de la Madeleine (1993m)

it starts with some hairpins not too hard (7-8%); just after, the percentage vary from 8 to 10% until you reach St-François-Longchamp (1450m). Then the slope is very regular (8%). The last kilometers seem never finish, and the wind is often an enemy near the top. The road is perfecly surfaced on this side.
On the paper, this southern road to the col de la Madeleine is one of the hardest climb of the Tour de France. Nevertheless, I must recognize that the sequence Télégraphe-Galibier is probably harder.