Rip Tides are the Most Deadly Natural Hazard in Australia

University of New South Wales researchers report that rip currents claim more lives in Australia each year than brushfires, floods, cyclones and shark attacks combined.

The research points toward the hazards of swimming in the ocean, especially when no life guard is present. An average of 21 deaths are caused by rip currents or rip tides each year in Australia, the researchers report. The number of lives claimed by rip currents is significant, more than 5.9 average annual fatalities from brushfires, 4.3 deaths in flooding, 7.5 cyclone-related deaths and one death by shark each year.

"Rips account for greater overall loss of human life than other high profile natural hazards. Yet they do not get anywhere near as much attention and dedicated funding," said Rob Brander, a coastal geomorphologist at UNSW and lead author of the study.

Brander and his team assessed rip current data from National Coronial Information System for the period between 2004 and 2011.

Across Australia's 11,000 mainland beaches, the researchers estimate there are as many as 17,500 rip currents in effect at any given time.

Swimmers caught in rip currents can easily be swept away far distances out to sea, leading to exhaustion, panic or, as the data suggest, an average of 21 drowning deaths every year.

"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," Brander said.

The researchers obtained data for other natural hazards from the Australian Emergency Management Institute National Disaster Database to identify the average number of deaths per year cause by tropical cyclones, floods and brushfires each year from the late 1800s.

"Other types of hazards, like bushfires, have the capacity to claim large numbers of lives in a single event. 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," Brander said.

"As rip current are a global problem, it is hoped that this study can be applied in other countries to more appropriately place the rip current hazard in perspective with and context of other natural hazard types."

The research is published in the journal Natural Hazards and Earth Science Systems.