A Ten Tors trainer has spoken of the sudden dangers of the Walla Brook on Dartmoor where a teenage girl died.
by Jonathan Morris
BBC News, Devon
The girl, from Edgehill College near Bideford, was swept away by a torrent of water after heavy rain on Sunday.
She was taking part in training for the annual event which sees thousands of young people trek up to 55 miles (86km) across the moor in Devon.
Dave Berry, who was in charge of another group, told BBC News the brook can become a torrent in seconds.
Mr Berry called his group of 18 youngsters and four staff from Torquay Boys' Grammar School off the moor on Sunday morning, after camping overnight.
Three other groups, including 20 from Edgehill, were airlifted off the moor later in the day amid driving rain.
Mr Berry, who has taken groups on the moor for 30 years, was aware of how treacherous the Walla Brook, which was in the path of his group, could become.
"I know the Walla Brook well and it's wild," he told BBC News.
"One minute it is relatively quiet and the next it's a raging torrent.
"Two years ago after it had rained it had turned from a babbling brook to becoming impossible to cross and that's what we would have encountered.
"I just wonder if the Edgehill group would have tried to cross it if they had known that."
Three groups were airlifted from Dartmoor on Sunday
He said there were no stepping stones and after rain the bottom of the brook was covered.
He said: "Edgehill has been sending groups on the Ten Tors for as long as we have.
"They just seemed to be in the wrong place at the wrong time.
"It is a great tragedy and we feel for all those who were there and the relatives of the girl who died.
"I also feel for the school because they were giving the children a really good positive experience, but sometimes tragedy happens."
Mr Berry said that he had pulled his group off the moor at about 0830 GMT.
"The wind had been building up all night and by 0500 it was gales," he said.
"It was deteriorating badly and I thought it was prudent to pull them off."
He said making the decision was a judgement he thought hard about.
"The difficulty is that groups should experience testing conditions, because they are going to be subject them on the trek," he said.
"Some of the boys were disappointed, but there is a line you have to draw."