The Stelvio, one of the most iconic climbs of Italian cycling at an altitude of 2,758 metres, was supposed to end a 202km stage between Livigno and Santa Cristina Valgardena in northern Italy next Tuesday.
"Heavy recent snowfall followed by a rise in temperatures have increased the risk of avalanche," said organisers.
The peloton will instead travel to Giogo di Santa Maria, the new peak of this year's Giro at 2,489 metres, and the stage extended to 206km.