Canterbury 4x4 Events president Ash Sergeant, who was not on the expedition to the West Coast, said Mr Brons' main role as a navigator had been as an extra pair of eyes to look out for things the driver might not see.
Mr Sergeant travelled to the site yesterday. "The river was not what I would call excessively high, it was higher than normal ... but that river river goes up with the snap of a finger."
He was unable to say whether the conditions were safe to cross on Saturday, during the torrential rain.
"I cant make a call on whether it was a safe level, or not. They are all pretty well experienced guys, they have all got years of experience behind them, all got well set up vehicles. I would say the call they made would have been a well educated one."
He said it was more of a case of bad luck than being foolish.
Jeremy's father Timothy Brons told 3News that the last time he saw his son he was "grinning from ear to ear".
"Unfortunately I didn't even to get time to say goodbye to him because he was gone before I got home from work."