Surf's Up! Welcome to 50-Foot Waves, Washington

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

Twenty years ago, a big winter storm might generate 25-foot waves offshore of the Pacific Northwest. Scientists pegged 33 feet as the maximum in a 100-year storm. But the intervening years--and a strong El Niño weather pattern--brought 33-foot waves...and then some (see photos here). Now researchers at OSU believe that the maximum wave height in a 100-year event is 46 feet (or as much as 55, depending on how you measure).

The largest wave increase, in fact, centers on the Washington coast, down to northern Oregon, says Science Daily. Wave height has grown about four inches per year, for a total of about ten feet over the past three decades.

"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."

The change is a boon to storm watchers and shutterbugs, but the mundane result is coastal erosion that occurs two to three times faster than normal. That, in conjunction with the ongoing sea level rise from climate change, argues the NPI Advocate, means real money, as coastal development is damaged and roads wash away.

(In Seattle, it means asking how high our brand-new seawall needs to be. Dan Bertolet points out that while the new design assumes a 1-foot rise in sea levels, new models based on accelerating ice-melt data produce rises of over four feet.)

Not content with the prospect of a 50-foot wave hurling a pod of Orcas straight at you (I embellish, but only for the purposes of sensationalism), the researchers end by recalling that things can get worse: Our impending subduction-zone quake could well result in our coastline dropping a few feet, just as the waves are getting bigger.