Heavy snow, ice and sub-zero temperatures forced stage 19 of the Giro d'Italia to be cancelled on Friday.
The stage, from Ponte di Legno to Val Martello, had already been significantly amended after freezing conditions on the Passo dello Stelvio and Passo di Gavia made them unrideable.
With further snow falling and ice forming on the replacement climbs of Passo del Tonale and Passo Castrin overnight on Thursday, organisers later took the decision to cancel the stage altogether.
Saturday's 20th stage has also been altered due to the weather, with three of the day's four planned categorised climbs being cut.
The day will still end on the fabled summit finish at Tre Cime di Lavaredo, but the route will now not visit the Passo Costalunga, Passo di San Pelligrino or Passo Giau. The changes have led to an extension of the stage from 203km to 210km.
The two days had promised to be critical stages in the race for the maglia rosa and the changes have worked to the advantage of race leader Vincenzo Nibali (Astana), who holds a 4min 2sec over his nearest rival and now has only two, less challenging days to defend the pink jersey.
Another rider to benefit is Mark Cavendish (Omega Pharma - Quick-Step), who is battling with Cadel Evans (BMC) for the points leader's red jersey and has a slender lead of four points.
Two mountain stages on Friday and Saturday would likely have seen that deficit overhauled by Evans, but now with just one more remaining and then a sprint stage into Brescia on Sunday, the balance has swung back in Cavendish's favour.
Evans said of stage 19's cancellation: "It is always possible to pass those passes [Stelvio and Gavia] on a bike. But to have a good race and stay healthy and safe for everyone is really quite impossible.
"The organisers have done the right thing. For the communities who have invested to have a stage of the Giro, I'm sorry for them. But we can't control the weather."
Stages 19 and 20 are not the first days in this year's race to have been hit by bad weather, with torrential rain interrupting a number of previous stages.