Why This Year’s El Niño Could Mean Winter Flooding for the West Coast

NASA has issued a warning for cities on the west coast of America, including San Diego and Seattle, cautioning these hubs could experience as many as five major floods this winter.

The reason why is the El Niño climate system that originates in the Pacific Ocean but which affects weather patterns worldwide.

During an El Niño year, the trade winds over the Pacific Ocean die down, and the water warms up and sea levels rise, particularly around the equator. The change in ocean climate can push wet weather across the south and the Gulf Coast, but it can also lead to increased risk of coastal floods, particularly over El Niños' peak, which coincides with our winter.

On Thursday, NASA warned that cities on the west coast could, if El Niño peaks and strengthens, be hit by as many as five 10-year flood events this winter — these extreme weather events typically have a 10% chance of happening in any given year.

"I’m a little surprised that the analysis found these 10-year events could become commonplace so quickly," said University of Hawaii oceanographer and NASA sea level change science team member Phil Thompson in a statement. "I would have thought maybe by the 2040s or 2050s."

NASA said these kinds of floods could occur as often as 10 times a year along the west coast due to the effects of climate change by the 2030s — no El Niño necessary.

The situation could become even more dire by the 2050s, when strong El Niños could lead to up to 40 floods a year in that area, NASA warned.

"As climate change accelerates, some cities will see flooding five to 10 times more often," NASA scientist Nadya Vinogradova Shiffer said in a statement.

In June, the National Oceanic and Atmospheric Administration warned that there was an 84% chance of a stronger-than-normal El Niño developing during the 2023-2024 winter.