Four skiers were killed and three seriously injured Saturday in an avalanche in the Swiss Alps, where dangerous snow conditions have caused a series of deadly accidents.

The victims were part of a group of nine skiers that was swept away by the avalanche on the eastern slope of Piz Vilan in the eastern Swiss district of Landquart, police said.

Three of skiers were killed on the mountain. Four others were airlifted to hospital, where one person later died of his injuries.

All of the skiers were wearing beacons, which guide rescuers to avalanche victims.

Weather conditions in the Alps are particularly treacherous at the moment with avalanches killing three people at other Swiss resorts Thursday and Friday.