Sydney - The Australian surf kills more people than bushfires, cyclones, floods and sharks combined, according to a study released on Wednesday which found rip currents were far more likely to be deadly than other natural hazards.Australia is known for its destructive summer wildfires, storms and dangerous predators such as sharks which are common in its waters, but researchers at the University of New South Wales said there was an unheralded killer in the sea."Rips account for greater overall loss of human life than other high profile natural hazards," said lead author of the study, coastal geomorphologist Rob Brander."Yet they do not get anywhere near as much attention and dedicated funding."The study, published in the Europe-based journal Natural Hazards and Earth Science Systems, found that rip currents caused an average of 21 confirmed human fatalities per year in Australia.This compared with 7.5 deaths for cyclones, 5.9 for bushfires, 4.3 for floods and one for sharks, producing a combined total of less than 19.HazardRips are strong, narrow currents which pull swimmers away from the beach and can easily carry them well offshore, causing them to become panicked and exhausted - a state in which they can drown.The study analysed data from Australia's National Coronial Information System and found there was an average 21 confirmed deaths involving rips per year for the period of 2004 to 2011."And this is likely to be an underestimate because there has to be a witness to an event who saw the person was caught in a rip, and then this information has to be included in the coronial report," said Brander.Researchers then used information from the Australian Emergency Management Institute's National Disaster Database to identify the average number of deaths per year caused by tropical cyclones, bushfires and floods since the mid-to-late 1800s.The Australian Shark Attack File administered by Taronga Zoo in Sydney shows there has been an average of one death a year since 1962.Brander said while the rip data was only available for a shorter time frame, he was confident it was still the biggest hazard because many deaths caused by the currents were not officially recorded as such."Other types of hazards, like bushfires, have the capacity to claim large numbers of lives in a single event," said Brander."On the other hand, rip currents are almost always present and rarely result in more than one death at a time. But in the end, more people die as a result of them."Australia is famed for its 11 000 mainland beaches and an estimated 17 500 rip currents would be operating around the coast at any given time, the study said.Because rips flow faster than most people can swim, those caught in them are advised to float and signal for help.