A giant wave beneath the Pacific is heading toward B.C. Here's what it could do | CBC News

El Niño phenomenon could worsen the effects of storm surges and high tides

A giant underwater wave of water connected to this year's El Niño weather pattern is moving up the west coast of the Americas, raising alarm bells among scientists about how climate change is magnifying the impacts of the naturally occurring phenomenon.

A smaller wave already reached B.C. earlier this summer, and the next one is expected to arrive within one to two weeks, according to Bill Merryfield, a research scientist at Environment and Climate Change Canada.

During El Niño years, however, those east-to-west winds weaken or can reverse direction, allowing water to move east instead.

Sea-level monitoring data collected at Tofino, on Vancouver Island's Pacific coast, shows the impact of the earlier Kelvin wave in June.

Rather than a giant tsunami-like wave, the Kelvin wave temporarily raises sea levels.

"So if you put that 30 centimetres of sea level rise on top of a king tide, and then maybe you add a winter storm to that, which causes a storm surge, that's when you really start to get into trouble," he said.

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Those surges could be intensified by another effect of El Niño, further raising sea levels along the B.C coast. El Niño can strengthen northward winds along the coast, pushing even more water toward shore.

Local authorities there are placing emergency sand on beaches and expect the Kelvin wave to raise water levels six to 12 inches, the Associated Press reports.

The impacts of the Kelvin wave — and El Niño more broadly — could extend far beyond this season, Merryfield warned.

This will likely lead to 2027 becoming the warmest year on record "by quite a significant margin," Merryfield said, echoing similar warnings from other climate research organizations and scientists.