A few times a year the tides swell to levels much higher than are typical. These royally high tides are known as King Tides and occur over a few days period, typically in the months of November, December, and January.
With the King Tides, comes a whole host of changes to the coastline—local flooding, potentially increased erosion, and an overall increase in coastal hazard risk. However, King Tides are not necessarily something to run from. Many people flock to the coast to see the King Tides—the crashing waves and high surf are a definitive draw for many wave watchers.
King Tides also offers an opportunity to participate in some community science. Oregon King Tides Project, by the Oregon Coastal Management Program and CoastWatch, ask local Oregonians to snap some pictures of these extremely high tides and post them to their site. The goal of the project is to help coastal communities see their vulnerabilities, especially considering future climate change, so they can better adapt and prepare.
I wanted to learn more about sea level rise on Oregon’s Coast and experience the King Tides. So, I reached out to Alessandra Burgos of Cascadia CoPes Hub to see if she was open to a coastal ramble. She agreed.
It was time to head to the beach.
The Hike
- Trailhead: No Official Trailhead (Start on Avenue U and end at 12th Avenue)
- Distance: 1.5 miles one way on the pavement; the trail is level.
- Details: Park on the street or Public Parking at the North End of the Promenade. Public restrooms at North End. The promenade is open to hiking/running and biking. It is a popular spot and can be very busy.
Here Comes the King
It was a mostly sunny winter day during king tides week when Ali (Alessandra) and I met for a walk along the Seaside waterfront. If you want to talk about the ocean, it helps to have a clear view of it as you go.
Immediately, Ali’s dark brown eyes scanned the surf. The waves were coming in fast and there wasn’t much beach left uncovered. The tide was in, way in.
“I have never been here before,” Ali confessed, “but I would imagine the beach is usually much bigger.”
I tried to imagine what it might look like on a “normal” day. Even having been there, I couldn’t picture it.
“It would be nice to have a before and after,” I confessed.
Before and after picture aside, what we were seeing were king tides—unusually high-water levels at high tide that were expected to continue for the next few days. Begging the question—why?
Ebb and Flow
“What happens with tides is you have the gravitational pull of the moon, which is the strongest force,” Ali explained.
You may have heard that the moon creates tides—and this is mostly true. As the Earth rotates and the moon revolves around the Earth, its gravitational pull causes the ocean to bulge in the direction the moon is facing. This bulge is dragged around the Earth, like a magnet, as it rotates. There is also a bulge opposite the moon due to a lack of gravitational pull by the moon at this alignment.
However, that is not the entire story. As Ali explained: “Then you also have the gravitational pull of the sun, and even though the sun is bigger, it is further away so you don’t get as big a pull.”
However, when the sun, moon, and Earth are in alignment—you get a very high, high tide and a very low, low tide.
“For king tides, everything is in a perfect wonderful alignment,” Ali explained. “The moon is either a full moon or new moon… “ and is in line with the Earth and Sun. This causes a higher gravitational pull on the oceans causing these king tides.
At the time of our hike, it was a new moon. In a couple of days, the king tides would be at their peak.
“You can see over there it is higher than normal and those wonderful waves rolling in,” Ali pointed out toward the ocean waves again. They were really moving.
1 Tide, 2 Tides, 4 Tides, More
“Why do we get two tides here?” I asked next as we sauntered our way down a path to the packed sandy beach.
“That [slightly] has to do with where you are in latitude [because of how the continents are spread out],” Ali responded. “And [mostly] it has to do with the shape of the ocean basin.”
She also reminded me that we have two bulges making their way around the Earth in a 24-hour period, so there are both two high tides, and two corresponding low tides.
If there were no continents there would be 2 equally proportioned high and low tides every lunar day. The land masses block the movement of the tidal bulge resulting in different tidal patterns. On the West coast, we experience mixed semidiurnal tides meaning “You have a high, high tide, low, high tide, low, low tide, and high, low tide… four tides,” Ali listed the different tides, but it came out more like a tongue twister.
We were walking the beach during our high, high tide.
Most places on the Earth experience two tidal cycles. However, there are some places that have only one high tide due to the shape of the ocean basin. The Gulf of Mexico, for example, has diurnal tides, experiencing one high tide and low tide on a lunar day.
A Rough Start
Ali and I headed north along the sandy beach—the waves rolled in a short distance away from us. I asked Ali to share a little about herself and how she ended up in her current position.
“I grew up on the East Coast in Philadelphia. Went to school at Rutgers in New Jersey where I was a meteorology major,” Ali began.
She always had an interest in the weather and was planning to be a broadcast meteorologist when she finished college. But her plans changed when Hurricane Sandy hit New Jersey during her Freshman year of college.
“You saw the destruction… you saw all the trees down, during the night transformers blowing up, huge lines at the gas station… so that really formed what I wanted to do with my life.”
After that Ali became more interested in flooding and the Oceans. She went on to study oceanography at Old Dominion University in Norfolk, VA where she earned a Master of Science.
“Norfolk, VA is home to the largest Navy base in the world,” Ali explained. “So, as you can imagine, they were very interested in mitigating against sea level rise.”
Rising to New Challenges
After that, Ali moved to Washington D.C. as a Sea Grant Knauss fellow and was introduced to policy and worked on coastal resiliency issues.
“Then the pandemic hit, and I lost my job at the time,” Ali went on. “My friend was moving to Portland, and I always wanted to visit the west coast, so I packed up and came here.”
Finally, after a short stint at UC Santa Barbara, Ali was hired by Oregon State University in her current position—program manager for the Cascadia Coastline Peoples Hazard Research Hub, or Cascadia CoPes Hub.
“I have been there a year,” said Ali. “It has been a whirlwind of information… There are over 90 people associated with the project now.”
That is a lot to manage.
Collaboration
We hiked on, the sun warming us and the sand firm under our feet. Ali told me more about Cascadia CoPes Hub in fits and starts as we walked along taking in the scenery.
“In a nutshell, It’s a 5-year funded project from the National Science Foundation. We are trying to help coastal communities in the Pacific Northwest increase their coastal resiliency,” explained Ali.
Cascadia CoPes Hub is a newer collaborative (it started only about 6 months before Ali was hired) with multiple teams working on different aspects of coastal hazards research and outreach. Ali outlined the focus of each team.
Team 1 is geohazards. This team deals with research around earthquakes, tsunamis, and landslides.
Team 2 is coastal inundation. This team is looking at sea level rise, erosion, flooding, and overall storminess.
Team 3 is community adaptation. Team 3 wants to know what coastal communities are thinking—what do people value? What do they perceive as threats? And how do they get that information?
“This is where the social scientists live,” said Ali.
Team 4 is the STEAM team. STEAM stands for science, technology, engineering, art, and math. And the goal of this team is to bring underrepresented students into STEAM through a fellowship program.
And finally, Team 5 is community engagement and co-production.
“Coproduction is kind of a buzzword in research right now,” Ali explained. “Coproduction is working outside your discipline or field to create new ideas, solutions, and knowledge.” It often involves working with communities, state agencies, as well as other academics.
“We keep growing… There were 60 people when I started, and now there are 90 plus.”
Fading from Gray to Green
As we hiked on the broad plain of sand, Ali pointed out just how low-lying the beach was.
“If you look at the beach here,” she remarked pointing about, “we are as flat as flat can be.” Not a good place to be if the water came up too high in a storm—not a lot of protection.
However, looking over toward the City of Seaside, a low wall wrapped along the promenade in front of all the buildings—wouldn’t that offer some protection?
“Over there we have some seawall,” Ali said, pointing to the structure.
Ali referred to the wall as a form of grey infrastructure—a manmade structure built for, in this case, protection from flooding and storms.
“I am not a fan, personally,” she went on. “It has its merits in certain situations, but seawalls can cause more erosion of the beach… And how tall do you make it?”
As if on cue, the open sand we were walking shifted—wide mounds of grassy sand dunes rose up in front of us.
“These are green infrastructure,” Ali explained. “This will help block wave energy during storms.”
Unlike seawalls, dunes collect sand, rather than letting it erode. As natural-based features, dunes can grow and change over time. “Plus, it can help with habitat,” Ali added.
“Natural and nature-based features are what people are going more towards,” said Ali.
Ali also mentioned cobble revetments as another example of grey-green infrastructure. Essentially, a berm made of pebbles or cobbles mimics natural rocky beaches—water can move through the rocks, while sand can still build up.
“This is a great dune system,” Ali smiled as we headed through the dunes on what little beach was left.
On Shaky Ground
Soon the beach was all but gone and Ali and I decided to move to the pavement. We took some stone steps up and onto the Seaside promenade and continued our walk north.
As we walked, I asked Ali how she felt about the earthquake and tsunami hazards in the Pacific Northwest.
“It is definitely something I grapple with moving here,” Ali responded.
For those that haven’t heard, the Pacific Northwest is predicted to experience a high magnitude (possibly 9+) megathrust earthquake in the next 50 years. Current predictions estimate a 37% chance of a 7.1+ in the next 50 years according to oregon.gov. This will also result in huge tsunamis up and down the coast.
“What is most interesting about that is human perspectives—trying to understand how people see their vulnerability,” Ali continued. “It is easy to go day by day, especially if you don’t have past experience, to become very complacent.”
Keeping Perspective
I asked Ali what she thought people should be doing considering the megathrust and tsunami risk in Oregon.
She suggested keeping things in perspective. Yes, there is a risk associated with visiting and living on the coast, but it is still very small.
“Even on my drive down this morning, I get anxiety about coming over here,” she confessed.
However, she also knows that the odds are in her favor.
“I am more likely to get injured in my drive,” she added.
So, what should people visiting or living on the coast focus on? Being prepared. That is what her research cooperative is trying to do—help people know how best to do this on a place-by-place basis.
“What is the most important thing to know to prepare?” I asked.
“I think the biggest thing is to know your evacuation route,” Ali suggested. “Many people don’t know which way to go, especially if you’re visiting.”
Whenever the Cascadia megathrust earthquake hits, there will be little time to move to high ground—perhaps as little as 10-20 minutes at best. So, look at the evacuation maps ahead of time and have a plan A and a plan B.
On cue, Ali and I reached the end of the promenade trail, where a tsunami evacuation map was prominently posted.
“Moving here, I learned a lot more about earthquakes and tsunamis than maybe I want to know,” Ali laughed nervously.
I hear that, Ali.
Winter is Coming
Upon reaching the end of the trail, Ali and I about-faced for a return journey. This time we stuck to the paved walk that took us past the waterfront buildings—just a seawall in some spots for protection. Our conversation pivoted back to issues with high water. Ali was going to be speaking for the King Tides Community Science Initiative the following day about sea level rise, and with King Tides rolling in, it seemed important that we return to coastal inundation. Plus, I had a lot of questions.
On the top of my mind was winter—why were king tides so notable in the winter? I asked Ali.
“They are worse in the winter,” she responded, “because of the Earth’s orbit around the sun. We are closer to the sun in the winter so the gravitational pull is stronger… winter king tides are going to be stronger.”
One of the biggest Earth Science misconceptions is that the Earth is farther from the sun in the Northern Hemisphere winter, resulting in a change in seasons, but the opposite is true. Fun fact, seasonal shifts have more to do with the tilt of the Earth in relation to the sun. (You have just been scienced!)
Additives
Then of course there are the potential additive effects of storms which are more common on the Oregon coast in winter. I asked Ali to explain how storm surge and waves play a role in water levels.
“Storm surge is basically when you have a storm coming up the coast. You have low atmospheric pressure… with a lot more wind. The winds and pressure are forcing the water up—that is basically your storm surge. This can be coupled with high tides, which could make flooding worse.”
Ali explained how the wind is a result of pressure differences along the Earth, which are greater in the winter. And high winds equal bigger waves, which have harmful effects.
“Winter storms come through and produce a lot more wave energy,” Ali explained. “Those big waves can move sand around, cause erosion, and bring in a lot of debris.”
Both storm surges and big waves happen all the time, but with high tides, the consequences are magnified.
Rise Up
So, what about sea level rise, overall? What can we expect there?
There are two major contributors to sea level rise, according to Ali: 1) melting glaciers from Greenland and Antarctica, and 2) warming oceans.
How melting glaciers contribute to sea level rise is straightforward: glaciers add water from the land into the ocean, literally filling up the global bathtub, as it were.
Warming oceans affect sea level in a different way—causing the same amount of water to take up more space. As the water warms, the water molecules move apart in their higher energy state, taking up more space—something called thermal expansion.
Variability
Of course, there is some variability.
“Thermal expansion and ice melt aren’t uniform,” explained Ali.
Plus, there are other factors having an effect including changes in currents due to climate change and differences in vertical land movement.
There are sea level rise hot spots, as well as places that aren’t seeing any sea level rise at all.
Luckily, sea level rise has been slower along the Oregon coast overall—mostly because the land is rising too, counteracting sea level rise in some locations.
“Global mean sea level rise is 3.4 mm,” said Ali. “Oregon is not anywhere near that.”
Another El Niño
Then there is natural variability related to whether we are in a La Niña or El Niño year.
“ We have been in a La Niña for the past three years,” explained Ali.
La Niña brings colder weather and more precipitation to the Pacific Northwest.
“Which is great for skiing,” she chimed.
In an El Niño year, the oceans will warm—which could lead to greater thermal expansion and other issues associated with a warmer climate.
“And with climate change,” Ali added, “they may become more frequent and more severe.
“The biggest thing with sea level rise is your basic water gets higher—everything is happening on a higher base,” Ali explained.
In other words, a higher sea level means a higher storm surge and high wave energy eroding places it never reached before. King tides would be higher than they are now, and the next El Niño year, more severe.
Act Now
“What should we do?” I asked Ali.
“Our oceans are rising, that is fact,” Ali responded. “How much and when, is the biggest thing to think about, and what do emergency managers need to think about.”
More specifically, Ali recommended creating more natural and nature-based features on the coast as the first line of defense against inundation.
Another option—is managed retreat. Managed retreat is a planned process of moving buildings and people further inland to avoid hazards and risks.
“Managed retreat isn’t popular, but something to think about,” said Ali.
Ali was quick to add that, managed retreat isn’t something that she is in a rush to see happen in Oregon. Oregon isn’t facing a sea level rise crisis currently, so it probably isn’t as important a strategy right now. However, in the broad scheme of things, Ali was clear that managed retreat is important to adapt to sea level rise.
Predicting the Future
We were nearing our starting point on the promenade when we passed by a decorated tree or bush opposite the seawall. I snapped a picture. It seemed important for some reason. An emblem of the community perhaps?
Considering the community, what is the future of sea level rise?
“Sea level rise is exponential right now,” Ali told me as we walked. “Not on a linear increase. The rate is getting faster.”
“Why is that?” I asked.
“Warming and melt is on a lag, “ Ali explained. “Even if we stopped emissions right now, the oceans will continue to rise.”
And continue to rise, in theory, indefinitely.
“It is hard sometimes,” Ali paused. “People say ‘you are just doom and gloom’… There is a fine balance to walk—understanding the risks but knowing there is something we can do.”
Incoming Storm
Ali and I were still discussing sea level rise when we got to the point where we could see the waves and an access point to the beach.
“The water is straight up to the edge,” Ali proclaimed referring to our coastal view. “High tide today is about 8-9 feet. It is normally 2-4 feet.”
We headed down to check out the waves from a better vantage point.
As we walked out toward the pounding waves, Ali told me more about ocean waves and how they are generated.
“The wave energy is coming from the wind,” she began. The longer the fetch (the length of water that the wind can blow without being blocked) the more energy can be imparted into the ocean allowing waves to grow larger.
She went on to explain how the low-pressure system that generates the storm also has a small effect by pushing water up due to the inverted barometer effect.
“If you have low pressure the water is going up. High pressure it gets pushed down,” Ali described.
All that said, it was clear to Ali that a storm system was on its way. Waves were rushing up fast, breaking quickly, and curving ferociously—all signs of an incoming storm.
“They [the waves] are definitely stronger,” she remarked as we stopped and stared. “And it’s happening pretty far offshore… and getting those nice curves to them.”
I looked out toward the ocean to try and see what Ali was seeing. I hadn’t considered this idea before—that I could look at the ocean and predict the future.
Staring out at the rhythmic movement of the incoming waves—it all started falling into place.
Reflections
Our oceans are sending us warning signals. They warn us of storm systems coming through hours to days in advance. But more than that, they warn us of impending changes to our planet that we can’t afford to ignore.
Visiting the coast during king tides can be a lot of fun—people flock to the coast to see the massive waves and enjoy the pounding surf—but they are also a reminder that our planet is changing.
Our oceans are warming quickly, and the global sea level is rising, resulting in a multitude of changes to Earth and human systems.
The signs are there. We just need to learn how to see them.
Alessandra (Ali) Burgos a project manager for Cascadia Coastlines and Peoples Hazards Research Hub with Oregon State University. Ali earned a Bachelor of Science in Meteorology at Rutgers University and a Master of Science in oceanography at Old Dominion University.