An avalanche on Mont Blanc has swept two skiers to their deaths and left another injured, while a hiker was killed on another slope in the French Alps, authorities said.

The avalanche swept through an off-piste area of the Saint-Gervais-les-Bains ski resort on Thursday at an altitude of 7,545ft, the administration for the Haute-Savoie region said.

Dozens of mountain rescuers set out to search for skiers who were trapped, finding a man and a women dead and another person injured. Five other people were rescued.

An investigation has been opened into the cause of the avalanche.

Saint-Gervais Mayor Jean-Marc Peillex said the weather conditions were too unstable for such risky outings.

“It rained, it snowed, it was warm. There are enough marked paths to ski on,” he told BFM television.

“It’s terrible what happened. A family is decimated, and we are very sad in Saint-Gervais.”

To the north, a 31-year-old hiker was found dead after falling on the slope of the Ecrins mountain range.

The hiker had veered away from hiking paths to look at mountain goats with a friend, local broadcaster France-Bleu cited rescuers as saying.