ORSIERES, Switzerland (AP) – A Swiss tourist bus plunged into an Alpine ravine near the Great St Bernard Pass yesterday, killing 12 people and injuring 15, four of them seriously, police said.

Fourteen people survived because they had been thrown from the bus when it went out of control for still unknown reasons, police in the canton of Valais said.

“We can more or less exclude a skid,” said police spokesman Jean-Marie Bornet.

It had been snowing around the Great St Bernard pass – a main route through the western Alps near the borders of France and Italy – but the narrow, winding road was only wet when yesterday’s accident occurred, police said.

The bus, which was climbing toward the pass, slammed through a safety barrier and rolled over several times down a steep slope before dropping into the ravine and coming to rest in a stream, La Drance d’Entremont, 250 metres (800 feet) below the road, police spokesman Renato Kalbermatten said.

Rescuers descended by rope into the ravine and saved a 15th person from the wreckage, but the rest of the bus occupants were killed.

It was the worst bus accident in Switzerland since 1982, when 39 people were killed when a train hit a German tour bus.

Those killed included six women, five men and a 15 year-old boy, investigative magistrate Dominique Lovey told reporters.