Some 60 people are spending the night in cable cars near Europe's highest mountain, Mont Blanc, when a ride between two mountain peaks came to an abrupt halt, police say.
Georges-Francois Leclerc, the prefect of the Haute-Savoie region, said 110 people were initially trapped, but 65 were airlifted out by helicopters.
They are said to be French, Italian and American citizens.
Officials believe it will take "some time" to take everyone to safety, but rescuers are optimistic this can be done by nightfall.
The cable cars take 30-35 minutes to connect the famed Aiguille du Midi peak to the Pointe Helbronner.
The transport attracts 600 visitors per hour, and half a million each year.
However, local television stations have reported that the cables had become tangled in high winds.
The winds may have made the wires which support the cabin cars cross over.
"We will evacuate passengers by air, with police helicopters but also private ones called in by local authorities", a spokesman for the local gendarmerie police said.
Mathieu Dechavanne, the head of the cable company, said earlier that the authorities were "in contact with the clients [in the cable cars]".
He told La Vanguardia: "This will take some time but the weather is good".
The cable auto broke down on Thursday afternoon, possibly caused by a crossover of cables in the strong winds. "They have water and means to communicate".