Think Out Loud

Far-off storms could be one cause of sneaker waves on Pacific Northwest beaches

By Gemma DiCarlo (OPB)
Feb. 8, 2023 7 p.m. Updated: Feb. 21, 2023 4:03 p.m.

Broadcast: Friday, Feb. 10

A sign next to the beach warning of slippery rocks and sneaker waves.

In this photo provided by Oregon State University, a sign warns visitors about sneaker waves in Yachats, Oregon.

Tiffany Woods / Oregon Sea Grant


Most beachgoers in the Pacific Northwest are familiar with the phenomenon of “sneaker waves” — sudden, unexpected surges of water that can sweep people off their feet or pin them against rocks and dunes. Though they’re known to occur more often along the Pacific coast and during the winter, the waves’ origins remain somewhat mysterious.

Researchers at Oregon State University recently found that far-off storm systems could create the right conditions for sneaker waves to occur closer to home. We learn more from Tuba Özkan-Haller, interim dean of OSU’s College of Earth, Ocean and Atmospheric Sciences.

This transcript was created by a computer and edited by a volunteer.

Dave Miller: This is Think Out Loud on OPB. I’m Dave Miller. The National Weather Service has announced that there is a high sneaker wave threat for the Oregon Coast and the Long Beach Peninsula today and tomorrow. So if you have plans to go to the beach, they say make sure to stay alert and never turn your back to the ocean. My next guest hopes that these kinds of warnings can become even more accurate in the coming years. Tuba Özkan-Haller is a professor and interim dean at Oregon State University’s College of Earth, Ocean and Atmospheric Sciences. She’s part of a team that recently put out a new paper that explores how sneaker waves are created. She joins us now to talk about it. Welcome back to Think Out Loud.

Tuba Özkan-Haller: Thank you. Thank you for having me.

Miller: What’s your definition of a sneaker wave?

Özkan-Haller: Sneaker wave is really a colloquial term. And it refers to how the wave runs up the beach and whether or not it does so in a surprising manner. So if the way that sort of lapping up and down surprises people in any kind of way, catches them off guard, people tend to refer to the sneaker waves. It really is not a scientific term and in the science literature, we like to think of these things as unusually large run-up events.

Miller: I looked at the paper and I didn’t see the word sneaker wave there.

Özkan-Haller: Correct.

Miller: Unusually large run of events. But can we still call them sneaker waves for the purpose of this conversation?

Özkan-Haller: Absolutely.

Miller: For as much as we, especially the northwest, are warned about them, they still seem pretty elusive. Can you give us a sense for what it’s like to see one or to experience one?

Özkan-Haller: Imagine yourself going to the beach. My kids always like chasing the waves back and forth. So little kids might be chasing the wave down as it’s running back towards the ocean and then once it starts coming back towards them, they turn back around and then they run up the beach, being chased by the water. And so most of the time, the way we experience the run up is this lapping up and down of the waves in a sort of organized way. But sometimes the incoming wave manages to run up a lot further than any of the waves before it or after it and that tends to surprise those who are near the water. Maybe they were hanging out having a picnic or sometimes people like to sit on logs that have been washed up. So the beach that looked dry will now be inundated and sometimes to a height.

The sad consequence, then, is that as the wave starts running back down towards the ocean, it often holds people’s feet out from under them and draws them into the water. And of course, these are folks who are wearing coats and boots and that they get weighed down by all of that weight, the water is very cold. So surviving those conditions can become really difficult.

Miller: How often are these waves leading to injuries or deaths?

Özkan-Haller: One of the graduate students in my research group actually carried out a study where we went back in time to newspaper reports or any kind of Coast Guard reports or National Weather Service reports. So over the course of the time span of seven years – between 2005 and 2012 – 24 events were identified and many of them resulted in fatalities. And the region that we focused on ranged from Northern California, up to Oregon, all the way up to Southwest Washington. So three or four per year is probably about the number of times that I noticed that there is a significant event on the Oregon Coast.

Miller: What do scientists already know about when and where these waves occur?

Özkan-Haller: When you look at the events that my graduate student tracked, they tended to be - in Oregon, for instance - in the northern and the southern end of our coastline. Those are more susceptible, rather than beaches that are located sort of in the middle.

There are a number of features of the coastline that factor in Oregon, Northern California and Southwest Washington. Our continental shelf is really narrow so what that means is that not far from the coast, we are already in very deep water. That is one of the situations that has to be in place for these kinds of waves to occur and our beaches are very mildly sloping, that’s another factor that plays. But then of course the exact nature of the wave field that’s coming towards shore is another consideration.

Miller: I don’t remember hearing about sneaker waves until I moved to Oregon. Do they happen on the East Coast as well?

Özkan-Haller: They do not happen on the East Coast. On the East Coast, the continental shelf is very broad and the phenomenon that leads to these kinds of waves is basically dissipated away by that long broad continental shelf.


Miller: Why is it that sneaker waves are more likely to happen when the weather is mild and the wind is calm? In other words, they seem more likely to happen on nicer days at the beach.

Özkan-Haller: Yes. In reality, it’s really only on nicer days at the beach that, when the hazard is there, the people are also there. We tend to go to the beach on really nice days. But there is also an underlying connection because the kinds of waves that are more likely to lead to sneaker waves tend to be associated with far away storms. In other words, imagine really far away in the Pacific Ocean somewhere, there’s a storm brewing and waves are generated there and then those waves travel away from their region of generation and within a few days they will come to the Oregon Coast. So they are waves associated with far away storms. It is really during conditions when that is the case that sneaker waves are more likely to happen. If there was also a local storm superimposed–windy day and local waves generated–then the wave field gets kind of jumbled up and sneaker waves are less likely to occur.

Miller: What exactly did your team of researchers at OSU want to look into? What were the holes and knowledge that they’re hoping to fill?

Özkan-Haller: So this latest publication that just came out - my graduate student, with funding from the National Science Foundation, started really digging into one specific event. That event took place on January 16, 2016. It was one of the events that we had looked at when we chronicled seven years earlier. But this particular one, there was something special about it. There were seven video recordings over a five-hour time span that were posted on YouTube up and down the coast, in an area ranging from Northern California to Southwest Washington. They all recorded a very strong signal, so a sneaker wave [was] happening, inundating, and people trying to run out of its way.

So the fact that this wave was recorded up and down the coast made us think this is a big signal. Let’s dig into it and [see] if we can forensically figure out what was happening on that particular day.  We tested multiple hypotheses and one that was supported by the data really considered a phenomenon that’s related to the storm forerunners that arrived due to the existence of a distant storm.

Miller: It’s interesting, we’ve talked a lot over the last couple of years about citizen scientists or sort of volunteer-led efforts to help provide data to scientists. In this case, it seems like that was done almost without people intending to do so. All these different individuals using their cell phones, they capture what was happening because it was interesting or may be scary to them. And then after the fact, these grad students were able to use those videos to dig deeper into these waves.

Özkan-Haller: Yes, that is absolutely true. And some of these videos included information that was really useful verbally. So there was one video, for instance, where the person was saying how they were actually recording the second wave, that there was another one about five minutes earlier. So it gives us information about the time scales that are involved. So really, really useful.

Miller: But how much were you able to piece together–even with these videos–to figure out what was happening, say 10 hours earlier, that eventually led to these waves on the shore on this one day in 2016?

Özkan-Haller: So we actually were able to mine a lot of different data sources. We used wave buoy data from the National Weather Service. We used to tide gauge data from the tide gauge stations that are inside estuaries. We even looked at data from the tsunami warning system that exists offshore of the coast of Oregon. We can bring together all of those pieces of data. My graduate student at one point even decided to go out to some of these locations where these videos were shot to make sure we understood what the elevations were so that we could ascertain what the sizes and heights of these waves might have been. So really, we mined a lot of information for clues as to how it all hung together.

Miller: Is it possible for you to explain, in layperson’s terms, what you see as the most important findings?

Özkan-Haller: Yes. So one of the things we found out is that the pieces of the puzzle that can lead to a more accurate, more specific, more localized warning system is really what I’m looking for, right? And what we found out is that these are very long forerunners . . . and when I say they’re long, the time scale between successive wave crests is something like 22 to 24 seconds. And surfers know this: waves arrive in sets, usually 7 to 10 waves sets, it’s like the heartbeat of the wave field. These waves they’re the ones that you see when you’re standing on the beach, the breakers. But as it turns out, underlying these waves are much longer waves, waves that are as long as the sets themselves. So now you’re really talking about a few minutes. And the forerunners tend to pump a lot of energy into these longer waves that are actually hard to see visually because they hide underneath the breakers. But it is these really long multi-minute waves that are really the cause. They are the ones that don’t break, but instead they kind of slosh up the beach, like what happened in the bathtub as you’re getting into the bathtub.

Miller: So how close are scientists now to providing the National Weather Service with more accurate or more localized information so that they can give better warnings to all of us?

Özkan-Haller: The National Weather Service’s warning system has already been improved and in fact they are co-authors in the publication that just came out recognizing just how important the engagement with them was. And they provided just as much insight, energy and ideas into this work as we did from the academic side. So the National Weather Service’s sneaker wave warning system considers all of this newly found out information, but right now they’re still making forecasts that are sort of very broad in the sense that anywhere in Oregon it is likely that sneaker waves might happen. I would like us to get to the point where we can be a little bit more localized in our forecast, almost imagining the situation where you’re stepping out onto the beach and your phone gives you a little message or a warning signal that that beach between the hours of one and four is likely to be the locale of a sneaker wave.

Miller: And that specificity is in the realm of the possible in the coming years?

Özkan-Haller: I think we have some more work to do to get from here to there. But that would be the objective.

Miller: In the meantime, or even once we get there, what advice do you have for beachgoers in the Northwest when the threat is high?

Özkan-Haller: So definitely look at the National Weather Service’s forecast [and] their social media outlets. And before you go to the beach, checking out what the National Weather Service has to say is really just an important first step. I like watching the ocean from a lookout before I actually go and figure out where I’m going to be or where to put my picnic blanket. And if you’re watching the ocean from a lookout, you can sort of count the number of seconds between successive crests as they’re passing by at the fixed object, like a tree trunk. If that timescale is greater than 20 seconds, you really ought to be very careful on that particular day.

But then, once you’re on the beach, don’t turn your back to the ocean is certainly a really, really good piece of advice. But what I also like to tell people is that they need to really be thinking about an exit plan. Sometimes folks go into cove areas, areas where there’s rocks or logs or they are backed by dunes. So it’s hard to get to higher ground.  You really only have about 15 seconds to run out of the way if one of these waves was to occur just at that time when you’re trying to balance on a rock or looking into a tide pool for instance.

Miller: Finally, before we say goodbye, I look back on our files and I saw that the last time you were on was July of 2020 and at that point we were talking about university research restarting after a nearly complete shutdown at the very beginning of the pandemic. But even so, I now think of July 2020 as still basically the early days of the pandemic. Enough time has passed since then that I wonder if you can put it in perspective. I’m just curious how the pandemic changed research?

Özkan-Haller: Yes, that is such a good question. I think we got a lot more creative and inventive in the way in which we gain access to research results or even just the laboratories where the research takes place. But of all of the activities of a university, I think it was the research and lab that really returned earliest compared to our educational activities, even when we were not not yet carrying out classes and classrooms. We did kind of bring the research enterprise back because of its importance to the economy, because of its importance to progress, because of its importance to humankind. That was one thing that we did. What I really feel very proud about though in hindsight is that we had no outbreaks that were linked directly to the research enterprise and that tells me that the safeguards we put in place worked.

Miller: Tuba Özkan-Haller, thanks very much for joining us.

Özkan-Haller: Thank you for having me

Miller: Tuba Özkan-Haller is a professor and interim dean at Oregon State University’s College of Earth, Ocean and Atmospheric Sciences. She joined us to talk about recent research into sneaker waves.

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