A 32-year-old man was one of four lucky to avoid drowning on November 2 when the Moore River broke through the bar that regularly prevents it reaching the ocean.
The man and a 31-year-old friend were on an inflatable raft when the river bank broke and they were caught in the washout.
They were taken a few hundred metres from shore and the 32-year-old was washed overboard.
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READ NOWA police helicopter and Two Rocks Volunteer Rescue Group boat found the man, who had been in the water for about two hours and was about 500m offshore. He was treated for hypothermia.
Shire CEO Jeremy Edwards said the incident served as a warning for people to take care when undertaking water-based activities.
‘When the sand bar breaks, the process is fast and unpredictable, with a raging tide undercutting the bar to create an almost horizontal waterfall effect. If people are on top of the bar during the break they can be swept out to sea,’ he said.
Mr Edwards said the sandbar usually breaks in winter, spring and around Christmas time.
‘At times it will throw another foot of sand on top of the bank, which prolongs the break.’
‘It can take only a few minutes for the bank to break and, once the process starts, it can’t be stopped.’