"West from Ovaro: This is a very demanding climb, and one of the most difficult in Europe, usually compared to the Alto de El Angliru. It was featured for the first time in the 2007 Giro d'Italia. The climb starts in Ovaro in the Gorto valley, and is 10.1 kilometres (6.3 mi) long at an average of 11.9% with an elevation gain of 1,210 metres (3,970 ft) and a maximum gradient of 22%. The real climb however starts at Liariis, 8.5 kilometres (5.3 mi) from the summit. Shortly after the village, the road disappears into forest and gains 900 metres (3,000 ft) in the next 6 kilometres (3.7 mi). After this section, the road passes through three short tunnels, before a series of steep switchbacks immediately beneath the summit. The former rough asphalt between Liariis and the tunnels was replaced in 2007; that between the last tunnel and the summit had already been resurfaced by autumn 2005. The tunnels are now lit."
The mountain is an outright horror, when looking at the profile picture. While the total elevation gained of some 1200m's is comparable to other category 1 climbs, like the world famous Alpe d'Huez, the Zoncolan bridges this gain in a much shorter distance on the road, making for a mountain road whose slopes don't drop below 13-14% for kilometers in a row.
Under normal circumstances, this should be a climb for the pure goats, the Sastre's, the Simoni-types. We know Simoni is getting old though and may not be in the right shape for this. Sastre's shape.. who knows..
I am not expecting Basso or Vinokourov here: they carry just those few extra kilo's of body weight that will normally decimate your chances on a mountain this steep. Maybe Nibali.. again...