We have covered Hawaii snorkeling deaths for nearly two decades. In that time one pattern keeps showing up that most visitors have never heard of. It is called ROPE, Rapid Onset Pulmonary Edema, and it may explain why people keep dying in calm water without a struggle.
A reader named Renee put it bluntly under our recent full-face mask article. She said Hawaii owes it to visitors to warn about this, especially if they are snorkeling within a week of flying. Her comment was not about masks or Costco or carbon dioxide buildup. It pointed at something different that has been hovering around these deaths for years.
If you follow these cases long enough, you eventually run into the term ROPE or SIPE, swimming-induced pulmonary edema. If you are a first-time visitor arriving for a bucket-list trip, there is a good chance you have never heard either term before you step into the water. And that’s the problem. That gap between what researchers and water people know and what visitors are told is where this story lives.
What ROPE looks like on the beach.
One of the details that keeps showing up in suspected ROPE cases is not dramatic at all. A person swims in. They are not flailing. They are not screaming. They may look tired but controlled. They make it back to shore under their own power, walk up the sand, and then within minutes they deteriorate rapidly.
That does not match the public image of a drowning driven by waves or visible struggle. It looks like something internal, something happening inside the lungs rather than outside in the surf. Spouses in multiple Hawaii cases have described exactly that sequence, including the lawsuit we covered in Wrong Or Ignored Hawaii Visitor Drowning Warnings Refocused By Lawsuit.
Only after you look at that pattern does the physiology start to make some sense. When the body is immersed in water, pressure shifts blood toward the chest and lungs. Cold water can also tighten blood vessels. Add exertion, excitement, anxiety, or heavy breathing, and in some individuals fluid can move into the lungs, reducing oxygen exchange and making breathing progressively harder. The person may not feel panic in the classic sense. They may simply feel that breathing is suddenly much more difficult than it should be.
The flight-to-snorkel timing question.
The aspect that keeps rattling readers is the timing between arrival and first snorkel. Does it matter? Several researchers associated with the Hawaii Snorkel Safety Study (below) have discussed whether long-haul air travel could contribute to vulnerability, not as a single cause but as part of a group of factors. Dehydration, disrupted sleep, mild hypoxia from cabin pressure, and circulatory changes are all part of long flights visitors endure from the mainland.
Visitors often land, drop their bags at the hotel, and head straight to the water because the ocean is the main reason they came. That pattern is common and understandable, and it is rarely paired with a warning about pacing yourself after a five to six-hour flight. When you combine recent air travel, exertion in unfamiliar ocean conditions, and possible underlying cardiac or vascular issues too, the margin for error gets narrow.
The Snorkel Safety Study, funded in part by the Hawaii Tourism Authority, examined numerous drowning cases and identified patterns consistent with rapid onset pulmonary edema in a significant subset. It did not declare every snorkeling death a ROPE case, and it did not claim that flying automatically causes lung fluid accumulation. What it did say is that a meaningful number of cases did not fit the usual explanations and that immersion-related pulmonary edema is a plausible contributor in Hawaii waters.
When readers start seeing themselves in the findings.
After our recent article, BOH commenter Mike wrote urging us and others to read the Snorkel Safety Study and contact the project manager Carol Wilcox. He said he experienced what he believes were the beginning stages of SIROPE at Kealakekua last year, describing restricted airflow, pressure on his chest, rising carbon dioxide, dropping oxygen saturation, and increasing difficulty breathing. He made it out of the water. He is convinced others have not been as lucky.
Whether every such episode is clinically confirmed ROPE is not the point here. Rather it is that readers are recognizing their own near-misses in some of the patterns described by researchers. That is when the term ROPE moves from academic theory into one’s own experience.
What Hawaii tells visitors, and what it does not, yet.
There are snorkeling safety tips scattered across state and tourism websites. They tell visitors to check conditions, avoid swimming alone, and use proper equipment. They do not typically say that snorkeling within hours of a long-haul flight may carry additional physiological risk for some individuals. They do not typically explain immersion pulmonary edema in plain language that a first-time snorkeler would recognize and understand.
The Hawaii Tourism Authority funded the Snorkel Safety Study. Funding research and broadcasting findings are not the same thing. A visitor reading an arrival brochure or watching an in-flight video is unlikely to hear and recognize the words pulmonary edema, let alone understand how their recent air travel might factor in.
That disconnect is what fuels comments like Renee’s. “If incoming flights warned of dangers, people would stop dying. The fact it continues is unacceptable.” She sees a preventable pattern and asks why the warning is not delivered when it would matter most. Even if the medical community continues to debate mechanisms and percentages, there is a communication gap.
Where this leaves the conversation.
ROPE does not explain every snorkeling death, and no one should think that it does. At the same time, the idea that some drownings may involve immersion-related pulmonary edema is no longer fringe. It has been studied in Hawaii, funded by the state, and litigated in Hawaii courts.
Visitors will continue to land in the islands after a five-hour flight, grab a mask, and head straight to the water because that is just what people want to do on vacation.
If you were stepping off that plane tomorrow, would you want someone to tell you to slow down, hydrate, and think twice before pushing hard in the ocean on your very first day?
Snorkel-Study-Final-Reports-UpdatedGet Breaking Hawaii Travel News
Thank you for your continuing coverage of this little understood ocean safety concern. The Snorkel Safety Study identified five risk factors. First and foremost, the level of resistance to inhalation caused by breathing through a tube, i.e. the snorkel. Second, compromised heart health. Third, recent prolonged air travel. Fourth, Exertion, Fifth: Inexperience. In the end, the Study preferred the acronym SI-ROPE.: Snorkel Induced Rapid Onset Pulmonary Edema. That lays the cause squarely on the snorkel, where it belongs.
Thank you for this excellent but seemingly unpublicized information. I have retired friends visiting this week and it was an eye opener for them — and me. Little dips in the pool to start!
Yes.
I hate percentages prefer raw numbers 1,455,660 residents live on Hawaii 9 to 10 million tourist visit Hawaii annually. Between 2020-2024 187 residents died drowning in the ocean during the same period 362 tourist died drowning.
It seems as a whole the number of tourist visiting Hawaii verses drownings is actually quite low compared to the amount of residents that drown annually.
even though this is old news, thank you for keeping it in front of the publics eyes
Prevent the formation of the clotting before it begins on the long flight. Wear compression hose. Ask your physician if you can take some baby aspirin before flying. Get an aisle seat so you can get up and walk every hour or so. An ounce of prevention…
It’s a good idea but like the safety video on the plane, most people will ignore it. We’ve been told for Years that you should monitor your alcohol on a flight, but people still get blitzed. I also think that grown adults are responsible for their own safety and their children’s safety. If you are going on vacation it’s up to the adult to do their research. We have enough agencies tell us all the dangers of pretty much everything. I don’t think it’s the airline’s job.
Here is the truth. Not a brag, but I regularly swim laps, go about forty-five minutes straight, no stopping, doing freestyle, easy to moderate pace. There are some other good swimmers too. But I see the following every single day.
The overwhelming percentage of people? Utterly horrendous mobility in water. No exaggeration, a big, big percentage of people “swimming” are totally gassed doing two lengths of the pool. Most can’t even manage that.
Two primary causes. First, many are obviously out of shape. Some struggle just getting in the pool; they literally cannot climb a ladder in water. But another big piece is people unquestionably do not know how to properly breath and swimstroke in the water. They don’t know how to properly exhale CO2; they utterly fail to understand how to synchronize swimstrokes with their natural breathing rate.
Put these people in a Hawaiian ocean with mask and breathing tube. Death waiting to happen.
The people reading this article are probably not the ones that need to be reached. I’ve worked with the travelling public long enough to know that only a small percentage read signs, and even fewer believe the warning/instruction/suggestion applies to them. You can tell them verbally, “You probably shouldn’t go in the water here today. Look at those waves. Look at those rocks.”, or, “Please stay at least 10 feet from the turtles.”, and before you’ve gone 20 feet they’ve done just what you told them not to. There should be warnings and signage, but we have to accept that some people are impervious to good advice.
Bingo! After the recent (2) drownings in Maui- again, allegedly through the “coconut wireless” victims were using the “full-face snorkel mask”; I saw two older ladies (@late 60’s- early 70’s) with fully fogged up full-face masks at Black Rock, Ka’anapali. As I swam by them I did comment to them “please be careful with the use of those full-face masks- there have been two recent drownings attributed to them”. These ladies were heavy set and I could tell not the best swimmers. They pulled off their masks to chat and said “thank you, we appreciate your comment- we take them off every minute or so to be sure we release the carbon dioxide!”…well, that is great I am thinking, but if you have to take them off every minute to breath, is that not a problem?!!….grown adults came make their own decisions and assume their own risks..it is the children I am most concerned with, as they will have on whatever the parents put on them…
I’m curious how visiting sunrise or sunset factors into this?
Typical airplanes cruise with a cabin pressure equivalent to 8,000 feet. When we did the Haleakala sunrise, we arrived to the top before 3:30AM and left around 8:30. That’s about the same duration as a west coast flight, but more than 2,000 feet higher.
We’ve done the Mauna Kea sunrise too, with a much slower ascent and about 3 hours at the top. That’s a whopping 5,800 feet higher.
Mauna Kea — 3 hours at the top, or at the VIS?
It is far more dangerous to go scuba diving, then go to altitude, whether up a mountain or flying.
The dangers of altitude after flying exist if there is rapid ascent. The sunrise/sunset visits to Haleakala and Mauna Kea can potentially cause High Altitude Cerebral Edema in those who are susceptible to it. There is no predictive factor as to who will be affected. Even the most physically fit can develop problems with rapid ascent.
This is why, when going up Mauna Kea, tours stop at the visitor center for a while. Most visitors think it is to “acclimate” to the altitude. Not so. It is impossible for the body to acclimate within an hour. My sense is it’s an opportunity for the tour guides to assess participants, to estimate tolerance for short visit to the summit. The visit to the summit is short to avoid problems. Most visitors are going from sea level to 13,800 ft. elevation in a matter of hours. Google altitude acclimatization.
I certainly notice a difference if I give myself time to adjust. I feel better if I go slow. When we went up to the top of Mauna Kea, we spent 90 minutes at the Gilber Kahele rest area, and about 1 hour at the visitor center. We spent about 3 hours up top.
I remember my first trip to Jamaica, and wanting to learn to Scuba Dive, the first signs near the Dive Master Office, was not to Scuba until the 3rd day and not to Scuba inside of two days from Departure. That said, I’ve read about this on this Site before, and even just a month ago, education, may have to begin Inflight, In-Room and at Point of Sale of Fins, Masks and Snorkel’s! Unfortunately in today’s world, everyone is an authority, and few take responsibility, but for Snorkel Trips like Molokini, it should be a Q&A, when did you arrive, when are you leaving, have you Snorkeled before? Those are scary Charts!
People need to remember that just because someone does an activity and does nit have C an issue, has nearly zero bearing on any other human being. There are too many variables we cannot be certain of. So if you’ve run from the jet way into the water, snorkeled with your full face mask, and are around to tell us its safe, just don’t; plenty of people do heroin everyday and live, I doubt you want them telling your kids its safe.
I remember my first trip to Jamaica, and wanting to learn to Scuba Dive, the first signs near the Dive Master Office, was not to Scuba until the 3rd day and not to Scuba inside of two days from Departure. That said, I’ve read about this on this Site before, and even just a month ago, education, may have to begin Inflight, In-Room and at Point of Sale of Fins, Masks and Snorkel’s! Unfortunately in today’s world, everyone is an authority, and few take responsibility, but for Snorkel Trips like Molokini, it should be a Q&A, when did you arrive, when are you leaving, have you Snorkeled before? Those are scary Charts!
People still go to Molikini?
It was a grossly overpriced tourist trap thirty years ago. Even in the 1990s sea animals avoided it due to the tons of boats and “snorkelers” infecting the entire site.
Went once. Hated it because of massive crowds; have never returned.
I live on Maui and never had any desire to go to Molokini for the same reason you mentioned. I actually wonder who many accidents happened on those trips …
30+ Hawaii vacations and on the first full day I was in the water multiple times for hours. Neither my ex or I ever had a problem and we usually were in the air for almost 11 hours total. And this was always without having been snorkeling anywhere else between trips.
For some people maybe it’s a problem and maybe it has to do with how good a shape your overall health is too. I’m not denying that it can happen but just like Dirty Harry said, “A man has got to know their limitations”.
High blood pressure, heart issues and circulatory issues are all contributing factors. If you’re healthy, you’re much less likely to have an issue.
10-1 someone will finally nail down the correlation to dehydration. It’s quick here and we know that, but a lot of visitors coming in, loaded up on Mai Tai’s having a great time on vacation, sun, beach – Not drinking anywhere the amount of water they need, go out 100,200,300 yards and start cramping up. The rest is not fun.
This is a very important issue. Can you not coordinate with the airlines a short video explaining the facts and suspected factors of drownings on the islands and have that short video played to the passengers just before landing preparations. You have the attention of all passengers coming into the state of Hi and can educate them to ocean dangers. Many whom have never been to an ocean before.
Just a suggestion from a prairie gal.
Mahalo, R
I have been a dive instructor for 50 years. My conclusion on these fatalities went snorkeling or scuba diving, are all related to poor health and discomfort, while snorkeling. Many people believe snorkeling is simple, but there are some techniques that make snorkeling a much better experience, and can increase comfort in the water. Training for snorkeling, in my opinion, for most is essential. Also, getting a physical prior to exerting yourself in the water would be advised!
Even if only a small percentage of deaths involve ROPE, that’s still real. A simple warning costs almost nothing. On the other hand, I don’t want Hawaii turning into a place where everything comes with a warning label. And at some point adults have to assess their own limits. So it’s a tough call on this one.
Similar to the face mask debate. People latch onto one cause when it might be multiple factors stacking up. The flight timing is just another piece of the puzzle that’s worth paying attention to.
I experienced shortness of breath snorkeling recently the first day snorkeling and assumed it was just anxiety or something. Now I’m wondering if it was something physiological. I got out more quickly than I normally would have and everything was fine.
We still have to be careful not to overstate the flight connection. Correlation isn’t causation. Still, raising awareness about immersion pulmonary edema seems fair and reasonable.
We flew from Chicago, barely slept, and went straight to snorkeling on Maui. Looking back, that was probably not the smartest move and we’ll think twice about that next time and easy does it the first day. BTW no one suggested otherwise.
As a retired nurse in Hawaii I can tell you that ROPE is absolutely real. It doesn’t mean every snorkeling death is that, but it deserves more education. People should know the signs.
I appreciate you covering this because most visitors assume drowning means waves or rip currents or health issues. The idea that it can be something like this is not widely understood. That alone is worth talking about.
We landed in Kona last year and were in the water within two hours. No one said anything about waiting after a flight. If this research has been around, why isn’t anyone really mentioning it?