Erosion scientists: Roaring El Niño waves will be ‘big test’

Katie Wilson

Published on October 27, 2015 2:34PM

An ocean-front dune in south Seaview was reinforced with relocated sand and logs in 2014 in an effort to protect a portion of Discovery Trail immediately above the eroded area. When completed at this location about a decade ago, the trail was around 30 feet from the high-tide line. High surf driven by El Nino conditions this winter could sever the ocean-edge trail.

MATT WINTERS/Chinook Observer

An ocean-front dune in south Seaview was reinforced with relocated sand and logs in 2014 in an effort to protect a portion of Discovery Trail immediately above the eroded area. When completed at this location about a decade ago, the trail was around 30 feet from the high-tide line. High surf driven by El Nino conditions this winter could sever the ocean-edge trail.

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Few areas in Pacific County see as much change each year as the ominously named Washaway Beach neighborhood in North Cove, which has been eroding an average of 100 feet per year, according to the Washington Department of Ecology. As recently as last December, a couple watched their yard begin to break apart and crumble into the ocean, followed by their home.

Such events could become more common along the West Coast — and in places in Pacific County already prone to erosion and flooding — as the climate continues to shift and regular cycles like El Niño and La Niña become increasingly massive and severe, according to a new study released by the U.S. Geological Survey in September.

These climate events are already known to bring bigger waves, different wave direction, higher water levels and erosion, according to the researchers. Their study pulled together a massive amount of data, analyzing coastal data from 1979 through 2012 from 48 beaches across three continents and five countries bordering the Pacific Ocean.

As an extremely strong El Niño trundles toward the Oregon and Washington coasts this fall, the researchers believe these climate events could worsen coastal hazards such as erosion and flooding across the entire Pacific Ocean region for years to come, directly affecting places in Pacific County like the fragile Washaway Beach and Cape Disappointment State Park, and Ocean Shores in Grays Harbor County.

The last major El Niño in 1997-98 resulted in significant erosion near the mouth of the Columbia River, reversing a decades-long trend in which jetties caused the beach to grow westward, or accrete, as much as half a mile on the south end of the Long Beach Peninsula.

It’s possible to identify a relationship over the years between large El Niño/La Niña events and increased erosion and flooding, say coastal erosion researchers in Washington. It’s another thing to use that information to predict what could happen in the future, in a possible “new normal” of larger cycles, bigger storms, higher waves, battered shorelines.

Also, it isn’t yet clear what’s caused by climate change, setting a new pattern for years to come, and what’s an isolated quirk in the weather.


Predictions


“Shoreline behavior can be controlled by so many different factors, both locally and regionally, that it’s been difficult to isolate the signal until now,” said Patrick Barnard, lead author of the study and a coastal geologist with USGS. But, he added, the data they collected in the study will help them identify “how the major climate drivers affect coastal hazards across the Pacific.”

“This will greatly enhance our ability to predict the broader impacts of climate change at the coast,” he said.

And, said Ian Walker, professor of geography at the University of Victoria and a co-author of the recent study, “It’s not just El Niño we should be concerned about,”

The researchers from 13 different institutions including universities in New Zealand and Australia found that during El Niño and La Niña events all the Pacific Ocean regions they investigated were affected in some way. During El Niño years, though, the northern areas — the mainland of the U.S. West Coast, Canada, Hawaii and northern Japan — felt the brunt of the bigger waves and higher water levels. They dealt with more erosion and flooding as a result than communities in the southern hemisphere of New Zealand and Australia. Those areas experienced what the researchers termed “suppression” — smaller waves, less erosion.

But, when a La Niña arrived, generally this pattern would reverse. However, in some places, British Columbia for one, and in certain years, severe erosion and flooding occurred during both El Niño and La Niña storm seasons, Walker said.

“We need to prepare not only for this winter, but also [for] what could follow when La Niña comes,” he said.


Cape Disappointment


In the late 90s, a diverse group involving federal, state and local researchers looked at erosion issues in Pacific County and other nearby communities and published the Southwest Washington Coastal Erosion Study.

In that study, George Kaminsky of the Department of Ecology’s Coastal Monitoring and Analysis Program and other researchers predicted Cape Disappointment State Park near Ilwaco would lose 30 to 90 of the park’s 180 campsites by 2009 due to erosion. The Benson Beach area was believed to be particularly vulnerable and had, literally, been losing ground for years when the researchers examined historical data.

But that level of campground loss has yet to happen, thanks in part to the intentional placement of sand nearby, and several mild winters.

“Benson Beach is holding its own pretty well compared to what was happening,” Kaminsky said, but added, “It’s definitely still very susceptible to erosion.”

A number of campsites located near Benson Beach have always been a short walk to the beach itself. But, as erosion over the years reshaped the coastline and salt water now intrudes, damaging trees, many campsites have an ocean view park planners never intended.

“We’ve definitely seen an increase in popularity in a certain number of our campsites because they have a great ocean view now,” said Cape Disappointment State Park Ranger Tom Benenati.

But, when there are extreme weather alerts for the area and waves could be unusually high, park rangers have had to evacuate campers to make sure everyone stays safe. These are campsites that don’t even become available for summer reservations until springtime, after all the winter storms are over.

“We’re never certain they’ll be there in spring,” Benenati explained. It’s an “abundance of caution” for something that has yet to be a real problem, he said, but it’s been the park’s practice for several years now.


This winter


While studies have zeroed in to analyze coastal impacts at a local or regional level, the recent study of El Niño and La Niña events examined data from across the Pacific, looking at basin-wide patterns. And one goal, the authors say, is to use this massive amount of data to help the communities at risk better prepare for what might happen.

How storms brought by El Niño track across the region, the height of the waves, the severity of the El Niño or La Niña in any given year — all these things could make a big difference to the coast in terms of where erosion occurs and how severely.

This winter will be a big test, regional experts say. Because even if the broader questions about climate change remain unanswered, one thing is clear: higher waves in general are the new trend. And high water is just more ammunition for an El Niño storm.

“The elevated water levels are already here,” Kaminsky said. “I think the real question will be what will happen this winter.”

And still there’s the problem of the conditions on the day of an actual storm.

“Any one storm can cause more erosion in a single storm than you might average over a year,” Kaminsky said. Get the right storm on the wrong day and, he added, referring to Washaway Beach, “That 100 feet [of average erosion] could happen in one event.”



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