The Return of La Niña Spells Bad News for Drought Conditions in the American Southwest

Around 90 percent of the American West has been experiencing a scorching drought since June—but the relief of a wet, rainy winter isn't likely to come this year. In troubling news, scientists predict that La Niña will return for the second year in a row and prolong the drought well into 2022, reports Rachel Ramirez for CNN.

La Niña is a climate phenomenon in which powerful winds push warm water westward across the Pacific Ocean, causing cold water from the deep blue to rise to the surface near the Americas. This pattern sets off a cascade of weather changes across the globe. For the United States, La Niña causes uncharacteristically dry and warm weather in the Southwest, but stormier and colder conditions in the Northeast, Paul Duginski reports for the Los Angeles Times.

Last year, La Niña lasted from August 2020 to April 2021, and scientists have dubbed this back-to-back phenomenon a "double dip," according to a NOAA press release. Scientists predict that effects of this year's La Nińa will likely last until springtime, but won't be as strong as last year's event, Mike Halpert, deputy director of NOAA’s Climate Prediction Center, tells the Associated Press (AP). It's also no surprise that La Niña has made a return, since it's common for the event to last two years or longer.

This year, California, Idaho, Nevada, Oregon and Utah experienced their hottest summers on record, while 16 other states broke into their top-five, according to NOAA. Higher temperatures lead to more severe droughts, wildfires and water shortages, and La Niña will likely exacerbate those issues in the coming months, Gabrielle Canon reports for the Guardian.

"We're going to see conditions continue to dry out," David DeWitt, director at NOAA's Climate Prediction Center, tells CNN. "Places that have droughts will kind of persist or intensify, and places that don't have drought right now because it was recently ameliorated, we expect drought is going to redevelop."

Though La Niña occurs in the Pacific Ocean, it changes the weather on the East Coast, too, by affecting global jet streams, which can fuel the Atlantic Ocean's hurricane season, Jennifer Gray and Haley Brink report for CNN. So far, 20 storms have already been named this year, surpassing the average of 14 named storms per season. In addition to more frequent storms, hurricane season—which lasts from August to October—may be stretched out.

"Last year is a great example of this, as we had six hurricanes and five major hurricanes in October [to] November," Phil Klotzbach, a meteorologist at Colorado State University, tells CNN. "While we certainly don't expect to see that much activity the remainder of this season, the development of La Niña does leave the window open for more late-season storm activity this year."

Scientists are still working to understand if and how climate change affects La Niña, which occurs naturally. However, the World Meteorological Organization says that climate change can indirectly increase the impacts and severity of La Niña's effects, which is what scientists see playing out in the Southwest. 

"As long as greenhouse gases continue to accumulate in the atmosphere, the dice are loaded toward increasingly warmer temperatures, meaning less mountain snowpack, greater spring evaporation, and more intense summer heatwaves and wildfire activity," Park Williams, a climate scientist at the University of California, Los Angeles, tells The Guardian.

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Rasha Aridi is a science journalist based in Richmond, Virginia. She has written for Science magazine and Science News for Students. You can find her portfolio at rashaaridi.com.