Canyoning flood impossible to predict, experts say

Twenty-one people were killed by the flash flood Keystone Archive

Experts giving testimony at the Canyoning trial have said the guides could not have foreseen the flash flood, which killed 21 people.

Heavy thunderstorms and flooding are a regular occurrence in the Saxet Brook, taking place every few years, according to the first two witnesses to take the stand on Thursday in the trial in Interlaken.

Called to the stand by the defence, experts said the guides or managers of the extreme sport company, Adventure World, could not have anticipated such an event.

However, one expert, René Brinkmann – president of the guide training commission of the Swiss Alpine Club – said Canyoning trips should no longer be allowed to go ahead when a storm is brewing in the area, based on today’s knowledge.

Standard safety procedures

He said that, until the accident, only the scientific community would have known that such a flash flood could occur.

Brinkmann, who investigated and issued a report on the conditions in the Saxet Valley after the accident, also said the Adventure World guides had followed a set of safety procedures that were standard in the industry.

He added that a change in the water colour and a rise in the water level, two aspects which the prosecution has focused on in the proceedings, were not signs of an impending flash flood.

He was followed to the stand by an expert in hydrology and meteorology, Christoph Lehmann, who worked with him on the report.

He went a step further than Brinkmann by saying that, before the accident, the size of the wall of water which swept away the tourists and guides was an unknown phenomena in the Saxet Brook.

by Dale Bechtel in Interlaken