Rescue helicopters were forced to land further away from the avalanche site, and rescuers had to cover a greater distance on foot, police spokesman Jean-Marie Bornet told AFP.
They did manage to locate the skiers, who were all carrying avalanche victim detectors. Some were buried under as much as 2.5 metres of snow.
But four had been seriously injured and taken by helicopter to nearby hospitals, where three of them died.
"The fourth is undergoing resuscitation, so it's quite serious," Bornet said.
Around 30 rescue workers and several helicopters took part in the operation, police said.
Avalanches are taking a heavy toll in the Swiss Alps this winter season, killing at least 24 people, including Saturday's deaths, according to a count by Swiss news agency ATS.