Maximum height of extreme waves up dramatically in Pacific Northwest

January 25, 2010, Oregon State University
Wave heights are increasing off the Pacific Northwest, according to a new study at Oregon State University and the Oregon Department of Geology and Mineral Industries. (Photo by Erica Harris, Oregon State University)

A major increase in maximum ocean wave heights off the Pacific Northwest in recent decades has forced scientists to re-evaluate how high a "100-year event" might be, and the new findings raise special concerns for flooding, coastal erosion and structural damage.

The new assessment concludes that the highest may be as much as 46 feet, up from estimates of only 33 feet that were made as recently as 1996, and a 40 percent increase. December and January are the months such waves are most likely to occur, although summer waves are also significantly higher.

In a study just published online in the journal Coastal Engineering, scientists from Oregon State University and the Oregon Department of Geology and Mineral Industries report that the cause of these dramatically higher waves is not completely certain, but "likely due to Earth's changing climate."

Using more sophisticated techniques that account for the "non-stationarity" in the wave height record, researchers say the 100-year wave height could actually exceed 55 feet, with impacts that would dwarf those expected from rise in coming decades. Increased , flooding, damage to ocean or coastal structures and changing shorelines are all possible, scientists say.

"The rates of erosion and frequency of coastal flooding have increased over the last couple of decades and will almost certainly increase in the future," said Peter Ruggiero, an assistant professor in the OSU Department of Geosciences. "The Pacific Northwest has one of the strongest wave climates in the world, and the data clearly show that it's getting even bigger.

"Possible causes might be changes in storm tracks, higher winds, more intense winter storms, or other factors," Ruggiero said. "These probably are related to global warming, but could also be involved with periodic climate fluctuations such as the Pacific Decadal Oscillation, and our wave records are sufficiently short that we can't be certain yet. But what is clear is the waves are getting larger."

In the early 1990s, Ruggiero said, a fairly typical winter might have an offshore wave maximum of a little more than 25 feet. It was believed then - based primarily on data from two offshore buoys - that 10 meters, or 33 feet, would be about as large as waves would ever get, even in a massive "100-year" storm.

But then a major El Nino - which tends to bring larger waves, higher water levels and increased erosion - happened in 1997-98 and led to a string of "100-year" wave events of around and above 33 feet. Researchers went back to the drawing board, continued to study data and storm events, and now believe that the maximum waves the region may face could approach or even exceed 50 feet.

Increasing wave heights, they said, have had double or triple the impact in terms of erosion, flooding and damage as sea level rise over the last few decades. If wave heights continue to increase, they may continue to dominate over the acceleration in sea level that's anticipated over the next couple of decades. The prior concern about what could do, in other words, is already a reality. If sea levels do increase significantly in future decades and centuries, that will only add to the damage already being done by higher waves.

Waves pound a beach and structure between Depot Bay and Boiler Bay on the Oregon Coast. (Photo by Erica Harris, Oregon State University)

Exactly what impacts this will have in terms of beach erosion and shifting shorelines is difficult to predict, scientists say, because currents and sand move in complex ways, creating both "winners and losers" in terms of beach stability. But some effects are already visible, Ruggiero said.

"Neskowin is already having problems with high water levels and coastal erosion," Ruggiero said. "Some commercial structures there occasionally lose the use of their lower levels.

"Going to the future, communities are going to have to plan for heavier wave impacts and erosion, and decide what amounts of risk they are willing to take, how coastal growth should be managed and what criteria to use for structures," he said.

Hampering the research effort is the fact that two of the major buoys used for these studies, which are some distance off the Pacific Northwest coast and measure waves in deep water, were only installed in the 1970s. Even at that they provide two of the longest high-quality wave height records in the world. OSU researchers are studying historical records through climate data, old newspaper records and other information to try to recreate what wave heights and events were like going further back in time.

The largest wave height increases, scientists say, have occurred off the Washington coast and northern Oregon, with less increase in southern Oregon and nothing of significance south of central California. The study also noted that similar increases in wave heights have occurred in the North Atlantic Ocean, as well as the seasonal total power generated by hurricanes.

These issues do not consider the potential drop in land level that is expected to occur in this region with a subduction zone earthquake at some point in the future. Ruggiero noted that he did some research in Sumatra following the huge 2004 earthquake there - an area with geology very similar to that of the Pacific Northwest - and some of the shoreline had dropped from 1.5 to five feet. If and when that occurs, the impacts on shorelines could be enormous.

Explore further: Researchers Study Coastal Hazards of Increasing Wave Heights, Rising Sea Levels

Related Stories

New research sheds light on freak wave hot spots

August 5, 2009

Stories of ships mysteriously sent to watery graves by sudden, giant waves have long puzzled scientists and sailors. New research by San Francisco State professor Tim Janssen suggests that changes in water depth and currents, ...

Research pinpoints conditions favorable for freak waves

August 24, 2009

( -- Stories of ships mysteriously sent to watery graves by sudden, giant waves have long puzzled scientists and sailors. New research by Assistant Professor of Geosciences Tim Janssen suggests that changes in ...

NASA technology captures massive hurricane waves

September 26, 2006

A hurricane's fury can be relentless, from frightening winds, to torrential rains and flooding. These storms also create enormous ocean waves that are hazardous to ships. And through storm surges of up to 30 feet the storms ...

Height of large waves changes according to month

May 29, 2009

A team of researchers from the University of Cantabria, Spain, has developed a statistical model that makes it possible to study the variability of extreme waves throughout the year, according to the journal Coastal Engineering. ...

Sea level rise could be worse than anticipated

February 5, 2009

If global warming some day causes the West Antarctic Ice Sheet to collapse, as many experts believe it could, the resulting sea level rise in much of the United States and other parts of the world would be significantly higher ...

Recommended for you


Adjust slider to filter visible comments by rank

Display comments: newest first

2 / 5 (17) Jan 25, 2010
I thought this was a good study and good information Untill they linked global warming to wave height. They say the cause of these dramatically higher waves is not completely certain, but likely due to Earth's changing climate.

Then they go on to the most likely causes. I hate it when scientist link everything to the made up theory of AGW actually the fraud of AGW. Read Climategate
3.4 / 5 (10) Jan 25, 2010
well freethinking to be honest the world doesn't care about what you hate, or love in a scientific paper does it, same as it doesn't care about how i feel about it.
if your choosing to disregard AGW from your paradigm of reality as to a possible cause then thats your freethinking right to do so.

wondering if we're seeing a similar thing happening on the european side and how this might effect our wave building programs, there has been some mental surf in cornwall this winter.
2 / 5 (17) Jan 25, 2010
I hate dishonesty disquised as science. AGW is a scam to achieve political aims. Everyone who loves truth and science has to hate how leftist politics has corrupted climate science (as well as the social sciences). If waves are getting bigger, blaming a non-scientific cause shows that the science is bogus, and the researchers are just trying to climb on the AGW bandwagon for money.

If you dont believe that AGW is a scam for leftist politics then research Climate-gate or just read the latest where the UN so called scientists admit to lying to put leftist political agenda pressure on world leaders.

or the latest where so called scientists used selective temperature data (ie. lying again)

3.3 / 5 (15) Jan 25, 2010
after months of reading and hearing in other forums the claim that Global Warming(antropogenic or no) is junk science, I have yet to see any peer reviewed, published science specifically to the contrary. Just an over-reliance on claims of mis -representation or -interpretation(or both) of the data.
1.8 / 5 (15) Jan 25, 2010
Caliban, just read the links I've just supplied. They are todays news articles. If the truth about AGW doesn't convince you. Then nothing will. I've come to believe that convincing members of the AGW cult of the truth is just as hard as convincing members of the Jim Jones cult that Jim Jones is not God, and that drinking the cool aid is a bad idea.
4.7 / 5 (6) Jan 25, 2010
Ignoring the mandatory mention of AGW in almost every science story, what I find interesting is the continual underestimation of both the size and frequency of outlier events. The implicit assumption always seems to be the last 100 or so years for which we have data just happen to be an unbiased sample from which to extrapolate, yet there is zero reason to suspect that is the case. No wonder their forecasts are so far off.
1.6 / 5 (13) Jan 25, 2010
I agree with just_doug and Verkle. Quit blaming AGW, study more outliers. Its like buying insurance. Do we build for a once in 50, 100, 200,500 year event or not? Depends on the amount we want to spend on insurance.
5 / 5 (2) Jan 25, 2010
Are the listed wave heights specific to the Pacific?
I've seen a documentary on "rogue waves" with measured heights peaking at 30 meters in the North Atlantic and Southern Ocean.
5 / 5 (1) Jan 26, 2010
chris a much more interesting and relevant post then the previous ones, which have just gone on about AGW, which the main thrust of this paper isn't about!
it would seem some of you people dissing AGW being cited as a posible cause are doing no more then re-inforcing your own ideologies, care to post anything relevant to the article?
like i was saying we've had some mental surf this winter in cornwall, UK, with waves coming in on one storm at over 50ft, wholly incidental i know and we have got some big wave generators going in soon around here
3.2 / 5 (9) Jan 26, 2010
Caliban, just read the links I've just supplied. They are todays news articles. If the truth about AGW doesn't convince you. Then nothing will. I've come to believe that convincing members of the AGW cult of the truth is just as hard as convincing members of the Jim Jones cult that Jim Jones is not God, and that drinking the cool aid is a bad idea.

Like I asked- where's the science refuting GW?
1 / 5 (5) Jan 26, 2010
These large waves are a direct result of lumbar operations closing in the Puget Sound, I read it on a blog somewhere. Can't blame this on so called global warming :)
1 / 5 (7) Jan 26, 2010
Caliban and other AGW believers,
If you want to continue to believe in AGW then dont read this

Because the science is settled. There is No fraud. UN and other Environmental Scientists have no agenda, they only have peer reviewed studies of the hightest quality. They would resign if they purposely mislead, etc. etc.

Cool aid anyone?
1 / 5 (6) Jan 26, 2010
Also, AGW is responsible for rise in sea level so please AGW believers don't read the following

Al Gore wouldnt lie about inventing the internet, polar bears dying off en mass, or AGW. Al Gore is not getting rich, he is not living in a mansion flying private jets. Al Gore is more friendly to the environment than George Bush (please AGW believers dont find out about GW Bush's ranch and how it is much more environmentally friendly than Al Gores mansions are. You believe BW Bush hates the environment and Al Gore loves it. Truth cannot shake your belief.)

So back on point. We are finding Waves are getting higher. How high will they go, what can we do about it. Quite blaming AGW just to get funds. Blaming AGW just diminishes your own science.

1 / 5 (2) Jan 26, 2010
Again, grasping at straws. Discredited bunglers trying to influence policy is not refutation, and even less so REAL SCIENCE. The article you cite regarding mediterranean sea level fluctuation is so obviuosly flawed as to warrant immediate dismissal, based on the claim made by the author that the mediterranean is not subject to any tectonic activity!
1 / 5 (4) Jan 26, 2010
Exactly... where is the science for AGW. Show me a study that hasn't been tainted or bungled.
1 / 5 (2) Jan 26, 2010
So that's it? That's all you've got? "I'm rubber, you're glue"? Freaking 3rd Grade?
Don't forget your water wings.
1 / 5 (4) Jan 26, 2010
Typical progressive leftist tactic. 1'st make up facts. 2, Shout anyone who disagrees with your made up facts down. (Al Gores famous statement The debate is Over. 3, prevent those who have the facts from speaking (just look at those emails from top environmental so called scientists showing this tactic) 4, keep repeating the lie.

Goebbels would applaud Al Gore and the rest of the AGW progressive leftist crowd for doing such a good job.

Lets see,
UN Scientist admitted to using misleading information to influence political leaders.
Climate scientists caught deleting source data
Climate scientists caught preventing those that disagreed with them from being published
Climate scientists wont provide code for their models
Al Gore caught lying numerous times about the environment
Climate scientists caught using bad data
The world has been on a cooling trend last 10 years

Yet you believe... how much money do you stand to make on AGW?

1 / 5 (1) Jan 27, 2010
These large waves are a direct result of lumbar operations closing in the Puget Sound,

Well, at least their backs will feel better.
1 / 5 (2) Jan 27, 2010

Yet you believe... how much money do you stand to make on AGW?

Belief isn't at issue here.
Let's see the SCIENCE.
1 / 5 (4) Jan 28, 2010
Oh, just found the following information how the climate scientist hid climate data. If the data is good why would he want to hid it?


I agree... lets see the science.
not rated yet Jan 31, 2010
The reason these earth science articles fill up with comments is because they mention AGW. Other articles don't draw any special attention because their science is not tainted with scandal.

If you are authoring a study of, well, just about anything you should avoid casually linking it to climate science so that people will take your study seriously and evaluate it on its own merits.

Right or wrong, the UAE scientists discredited themselves and their field. It's going to take a long time to get over it.
not rated yet Jan 31, 2010
I find it tiresome that every article on the internet, including this science-focused website, gets hijacked by emotional tirades whenever "global warming" is mentioned. I'd like to see the discussions on PhysOrg remain theory-based and not digress into personal opinions and regional political agendas. My suggestion is that readers reinterpret every mention of "global warming" as "the theory of climate change". By including the word "theory", the topic remains open for revision by ongoing evidence and science. The term "global warming" is problematic, when the theoretical global consequences are more accurately represented by the term "climate change."

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.