PONTE DI LEGNO, Italy — Heavy snow forced Giro d'Italia organizers to call off Friday's mountainous stage 19 from Ponte di Legno to Val Martello. “Due to adverse weather conditions and, in particular, snow on the stage route in its entirety, stage 19 ... has been canceled,” race organizers RCS Sport said in a news release Friday. Poor weather had already led RCS to make changes to the stage-19 route Thursday, canceling two of the three major mountain climbs, the Gavia and Stelvio, but they had hoped to retain the final ascent to Val Martello. However, major overnight snowfall, temperatures well below freezing on the major mountain passes and sleet falling in the region's valleys early Friday caused the entire stage to be canceled, the first time that had happened since 1989. Overall leader Vicenzo Nibali applauded the organizers' decision, saying: “The conditions are really extreme and so I think they've made the right decision. “They'd already altered the stage route but because of the weather conditions and the snow we can't do the stage,” said the Italian, speaking at his team hotel. Racing will resume Saturday, with a third straight mountainous stage finishing at Tre Cime di Lavaredo but all the climbs leading up to it will be cancelled because of the poor weather. The race, rocked by the news of former winner Danilo di Luca's positive test for the banned blood booster erythropoietin (EPO) Friday, is due to finish in Brescia Sunday. Nibali leads by more than four minutes ahead of Australia's Cadel Evans and Colombia's Rigoberto Uran. Former Giro d'Italia winner Di Luca tested positive for EPO in a surprise test at his home before this year's race, according to the organizers. If confirmed in a backup “B” sample, Di Luca risks a lifetime ban since this is his third offense. The 37-year-old Italian rides for the Vini Fantini squad. The test was carried out April 29, five days before the Giro started, and the result drew a harsh rebuke from Vini Fantini team director Luca Scinto. Di Luca stands 26th overall, 33 minutes, 33 seconds behind overall leader Nibali. In 2009, Di Luca was given a two-year ban after testing positive during the Giro for CERA, an advanced form of the blood booster EPO. That ban was subsequently reduced by nine months after he collaborated with Italian anti-doping authorities. And after winning the 2007 Giro, Di Luca was banned for three months later in the year for frequent visits to Carlo Santuccione, a physician at the center of a four-year doping investigation. Seemingly headed for retirement just a few months ago, Di Luca signed with Vini Fantini just a few days before the surprise test. — Agencies