All three of the victims were Austrians who had arrived in the area the previous day, according to Italian media reports citing mountain rescuers on Thursday.
The avalanche hit the Gran Zebrù mountain at 3,200 metres above sea level, where the group was skiing. Hikers walking nearby saw the avalanche happen and alerted rescue teams, who intervened using helicopters.
Two of the skiers were dead by the time rescuers extracted them from the snow about 40 minutes after the incident, while the third, a woman, died of her injuries at a hospital in Trento.
This is the third deadly incident in the South Tyrol mountains in the past week: on Sunday a woman was killed on the Austrian side of the pass and last Wednesday a snowboarder died in an avalanche. The area is currently at a moderate risk of avalanches, according to authorities who have ranked it as a level 3 risk on a 1-5 scale.
Gran Zebrù is the second highest peak of the Ortler Alps, reaching a height of 3,851 metres.
It has been the site of deadly avalanches in the past. In 2013, six people were killed in two separate avalanches while in August 1997, seven people died in avalanches on what was the deadliest day in the mountain's history.