Colombians are dominating the Giro d'Italia with Nairo Quintana winning the 16th stage to take the overall lead from countryman Rigoberto Uran.
Quintana, last year's Tour de France runner-up, pulled away in a controversial descent from the Stelvio pass and increased the gap in the final climb of the 139-km trek.
There was confusion as organisers appeared to neutralize the race during that descent, made dangerous by the terrible weather conditions, but then told teams to ignore the instruction.
Riding his first Giro, Quintana finished the stage eight seconds ahead of Canada's Ryder Hesjedal and Frenchman Pierre Rolland.
Quintana now leads Uran, who finished the stage in ninth place, by 1:41 with Australian Cadel Evans in third place overall 3:21 behind.