Rising Sea Levels on the West Coast: Understanding Kelvin Waves and Their Impacts
SEATTLE (AP) — Significant challenges are ahead for coastal communities along the West Coast, as projections indicate that sea levels could rise by as much as one foot this month. This is due to a series of warm water pulses known as Kelvin waves, which are expected to affect beach conditions and flood risk in regions already grappling with the effects of climate change and El Niño.
What are Kelvin Waves?
Distinct from tsunamis, Kelvin waves resemble a gentle sloshing of water rather than crashing waves. Conceptually, they are a surge of water that lifts sea levels as they progress along coastlines. Such waves are frequently observed during El Niño periods, and the current super El Niño may exacerbate their effects.
Current Predictions and Movement
Over the next week, forecasts suggest a northward movement of these 6-inch to 1-foot surges along the California coast at approximately 6 miles per hour (9.6 kilometers per hour), impacting areas in Oregon and Washington as well. Experts anticipate these pulsing waves to continue through February.
Michael Jacox, a research oceanographer with the National Oceanic and Atmospheric Administration Fisheries’ Ecosystem Science Division, explained, “It’s not that this Kelvin wave is going to come and flood anything on its own.” Instead, he emphasized, it raises the baseline sea levels to which storms and high tides will add additional height.
Formation of Kelvin Waves
Kelvin waves are naturally occurring phenomena associated with El Niño, which involves warming ocean waters. Their formation occurs when the trade winds along the equator change direction. These winds conventionally push water westward towards Asia, but shifts in wind strength can cause this water to reverse direction and flow back east toward South America.
Subsequently, the wave propagates along the coasts of North and South America. According to Dillon Amaya, an assistant professor in the Department of Marine, Earth, and Atmospheric Sciences at North Carolina State University, the wave is not visible to observers but resembles a broad pancake, extending 12 to 20 miles (19 to 32 kilometers) offshore.
Implications for Coastal Communities
Coastal communities are already contending with rising sea levels, which have heightened risks of beach erosion, particularly in places like San Clemente, California. As Amaya notes, “People are on edge,” anticipating increased flooding and erosion as elevated sea states pose greater risks.
According to Sean Vitousek, a research oceanographer with the U.S. Geological Survey, the combination of rising sea levels, larger waves from the North Pacific swell, and large spring tides from October to February could lead to exceptional erosion along the West Coast. Historical patterns suggest that previous major El Niño events—specifically those of 1982-83, 1997-98, and 2015-16—coincided with significant beach erosion.
Responses to Potential Impacts
Officials in Southern California are already preparing for the impending rise in sea levels. Authorities are actively placing emergency sand on beaches, with predictions of increased water levels ranging from six to 12 inches. California Governor Gavin Newsom declared a state of emergency in late September, citing the need for swift action to safeguard communities as conditions are expected to worsen.
In Washington state, experts are coordinating disaster response plans, although no special preparations have been initiated as of now. The severity of damage from the Kelvin waves will largely depend on weather conditions and the intensity of related storms.
Conclusion
The season ahead may prove to be one of the most consequential periods related to El Niño. While it remains uncertain if this winter will break records for wave activity, current indications suggest that this may be one of the largest instances of the phenomenon on record.
For more detailed updates and further information on the effects of climate change on coastal regions, please visit this source.
