The area is close to Mont Blanc on Italy’s northern border with France.
Rescuers found two other skiers alive and they are in good condition, sources said.
The pair of surviving off-piste skiers sounded the alarm shortly after the 1pm avalanche and told emergency services about the other two members of their group, one of whose body has been recovered, the sources said.
The group hit by the avalanche is from northern Europe.
Low-lying clouds had prevented helicopters from reaching the scene, Courmayeur Mayor Roberto Rota told Sky TG24, with rescuers getting to the site by snowmobile.
The avalanche risk on Sunday for the area was believed to be at level-three, or 'considerable' danger, on the scale of five risk levels — low, moderate, considerable, high and very high — used by the European Avalanche Warning Services, Rota said.
