Strong winds probably triggered the chairlift accident in the Bernese Oberland that killed a German tourist and injured three other people on Thursday.
There is no evidence to suggest a technical defect in the Fallboden installation above the ski resort of Grindelwald, according to Joseph Zeder, who is leading an investigation into the accident.
"We are working on the assumption that the wind was a factor," he said on Friday.
The three injured - a German woman and an Australian couple – were taken to hospital, with the German in a serious condition.
After an initial inspection on Thursday, Zeder remarked that a cable had apparently jumped off a guidewheel on one of the chairlift's support towers that rise up to 14 metres above the slopes leading to the Kleine Scheidegg pass.
Rescue officials said 75 passengers who were stranded on the chairlift had to be evacuated by ground-based specialists as high winds made the use of helicopters too dangerous.
The national weather centre, MeteoSwiss, said winds had reached speeds of 90 kilometres per hour when the accident happened.
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