The man was skiing with three others in the Plan de Fou area of the Nendaz-Quatre Vallées ski area that links with Verbier, at an altitude of around 2,500 metres, cantonal police said.
The man was buried by an avalanche in the off-piste area triggered around 2.30pm, police said.
The three other skiers were not affected.
The victim was carrying an avalanche victim detector device, police said.
The force released a photo of a steep slope where the accident occurred.
Earlier the same day, another avalanche swept six skiers down an off-piste slope in the Mont Fort section of the Verbier ski area, seriously injuring two of them.
The skiers, aged 15 to 55, triggered the snow slide at the 3,100-metre level while climbing with skis over their shoulders up the Bec des Etagnes, cantonal police said.
Four of the skiers were completely buried, police said.
Two of the most seriously injured ones were transported to Sion hospital, while two others were flown by helicopter to the Martigny hospital.
The incidents follow the death of a 52-year-old Valais woman who was buried by an avalanche while skiing at Zinal, another Valais ski area, on Tuesday.
Yet another skier remains missing after being carried down a slope by an avalanche at the Saint Luc resort, near Zinal, on February 4th.
Recent heavy snowfall in the Swiss Alps has raised the risk of slides on steep mountain slopes.