Climate change producing extreme wave threat along Northwest coast
January 25th, 2010 by Jim JustScientists have upped their estimates of the waves that a “100 year event” might produce along the coast of the Pacific Northwest. Their finding heighten concerns for flooding, coastal erosion and structural damage.
Waves crawl up against the lower level of a structure in Neskowin, Oregon, during a storm in January, 2008. (Photo by Armand Thibault, Neskowin)As recently as 1996, the maximum in ocean wave heights was estimated to be 33 feet. 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 conclude that the highest waves may be as much as 46 feet and the 100-year wave height could actually exceed 55 feet. Impacts of the bigger waves would dwarf impacts expected from sea level rise in coming decades.
Over the last few decades, increasing wave heights have had 2 – 3 times the impact of sea level rise in terms of erosion, flooding and damage. The largest wave height increases have occurred off the Washington and northern Oregon coasts, with less increase in southern Oregon and nothing of significance south of central California.
Possible causes cited are changes in storm tracks, higher winds, more intense winter storms, or other factors probably related to global warming but also possibly related to periodic climate fluctuations such as the Pacific Decadal Oscillation. What is clear is that waves are getting bigger.
The significant rise in sea level expected over future decades and centuries will only add to the damage already being done by higher waves.