Authorities in canton Ticino have begun an investigation into the deaths of two people in a canyoning accident in the Osogna valley, officials said on Wednesday.
A 42-year-old man and his 16-year-old daughter died after canyoning on Tuesday in the Ticinese valley. Their bodies were located in the evening, after a rescue team and helicopter were dispatched to the area.
The victims had been taking part in an expedition with three other people. Police in Ticino said the accident apparently occurred after the group was surprised by a strong wave.
The area where the accident occurred is close to a power station. But Samuele Szpiro, an engineer at the power station, ruled out that any work was taking place at the time of the tragedy which could have caused water levels to rise.
Szpiro added that he did not think the weather was responsible for any abnormal flow of water at the time of the accident.
Local power stations said they were willing to help the cantonal prosecutor's office which has opened an inquiry into the matter.
Blenio and Maggia power stations reportedly asked Ticino authorities to ban canyoning near the local reservoir in May last year.
In July 1999, 21 people, aged 19 to 32, died in a canyoning accident near Interlaken, after being caught in a flash flood. It was the worst canyoning accident ever to occur in Switzerland.
The accident raised questions about the security surrounding adventure sports in Switzerland, and whether measures should be introduced to supervise the companies which organise such expeditions.
Analysts say the latest incident is likely to prompt further discussion of security issues.
A memorial park was opened in July near the town of Wilderswil near Interlaken to mark the second anniversary of the deaths of the 21 victims of that canyoning disaster.
swissinfo with agencies