Uptick in tourist snorkeling drownings in Hawaii revealed to have unexpected causeAs summer kicks into high gear, authorities push ocean safety amid alarming drowning figures

July 25, 2022

Puu Kekaa, also known as Black Rock, juts out into the Pacific Ocean on Kaanapali beach in Maui.

Dusty Pixel photography/Getty Images

By Andrew Chamings

July 12, 2022

Drowning is far and away the leading cause of death for tourists in Hawaii.

The state’s Department of Health data shows that between 2009 and 2018, over 45% of tourist deaths on the islands came from drowning. (The second most frequent cause of death was motor vehicle accidents, at around 10%.) The data shows that of 206 snorkeling-related deaths over that decade, 189 were non-residents.

Many of those deaths occur while snorkeling, with the number of fatalities increasing sharply over recent years. At Maui’s idyllic Puu Kekaa, pressure has recently been put on authorities to increase the presence of life guards after the beach was described to SFGATE by authorities as “the No. 1 drowning capital in Hawaii.”

Last month, a California man was found dead in the water while snorkeling near Maui’s Kaanapali Beach.

But a mystery around the specific cause of death in these snorkeling fatalities  — wherein the victim is often found to have not struggled or shown any distress signals before succumbing to the water —  has now been revealed.  

three-year study by a subcommittee established in 2019 by the state Department of Health found that tourist snorkeling deaths are largely not due to the inhalation of water, but instead the result of low oxygen levels in body tissues prompted by excess fluid buildup in the lungs. The condition is known as hypoxia induced by rapid onset pulmonary edema, or ROPE.

The study rebutted the common thought that drownings were caused by inexperience on the part of the swimmer, who may have inhaled water. Factors that may cause a fatal case of ROPE include increased exertion, the snorkeling equipment’s resistance to inhalation and pre-existing conditions, the study found. This last factor explains why many snorkeling deaths are found among middle-aged men with an increased chance of heart conditions. 

The study also states that data “strongly support that possibility” that recent long-distance air travel may also increase the chances of hypoxia. This conclusion goes some way to explaining why snorkeling deaths are more prevalent among tourists. 

“It is not unusual to find a snorkeller motionless in calm conditions, and not very long after entering the water. Often there are no signs of distress,” the study said. 

The Snorkel Safety Study describes the difference between drowning by aspiration and ROPE: “Drowning by ROPE does not necessitate either submersion in or inhalation of liquid. Rather, it is a respiratory impairment that can be triggered by snorkeling,” the research group states. “Its progression is quick and quiet.”

Project director Carol Wilcox told Honolulu Civil Beat that she herself experienced ROPE while snorkeling the day after taking a seven-hour flight from Canada. “I started to hear this huge heartbeat in my ears, like deep drums … I knew I was going to die,” Wilcox told the outlet. She survived thanks to a beachgoer pulling her out of the water.

The typical sequence of a ROPE-induced drowning is a shortness of breath and loss of strength, followed by a feeling of panic or doom, followed by diminished consciousness. 

The study published multiple accounts of tourists who had near-misses while snorkeling around the islands that corroborated the ROPE theory. 

“About 20 yards offshore I was struggling to catch my breath. I was unable to call out or wave,” an unnamed visitor who had snorkeled 20 times told the researchers. “My arms were leaden…a wave pushed me to shore. I went unconscious.” That incident occurred in calm waters. A beach attendant applied oxygen on the sand before the individual recovered in hospital. 

Of 131 survey participants who had near-misses in the ocean, only one was found to have inhaled water. 

The study advised several cautionary steps that can be taken to avoid snorkeling accidents, including swimming with a buddy and staying where you can comfortably touch the bottom. It also states that “it may be prudent to wait several days after arrival in Hawai’i by air before snorkeling.”

Find the full report here.