A police inquiry has found that one of two deadly avalanches in the Bernese Alps on January 3 was triggered by ski mountaineers.

A first avalanche in the Diemtig Valley was set off as eight skiers followed an existing trail towards Drümännler. Two of the mountaineers caused a block of snow to shift and were carried away with it.

As the rest of the mountaineer group and other people in the area went to help, a second avalanche was set off from another hillside. This avalanche buried 11 people including a mountain rescue doctor who had arrived at the scene. The inquiry found the second avalanche was not set off by people.

Nine people were pulled from the snow, one of whom had died. Three people later died from their injuries. Another three bodies were found two days later.

It is the most serious avalanche accident in Switzerland since February 1999 when 12 people were killed in the Val D'Hérens in canton Valais.

swissinfo.ch and agencies

In compliance with the JTI standards

More: SWI swissinfo.ch certified by the Journalism Trust Initiative