After months of slight temperature shifts in the Pacific Ocean, La Niña has officially returned — the climate pattern that typically drives drought in Southern California.
The National Oceanic and Atmospheric Administration announced Thursday that La Niña conditions had arrived, a possibly foreboding sign for the Southland.
The southern half of the Golden State still has not bounced back from the last year of below-average rainfall, and the reemergence of the ocean phenomenon could mean more drought, with another drier-than-average winter.
The previous La Niña — active from January until about April of this year — “was a substantial player” in the region’s dry winter, said Emily Becker, research associate professor at the University of Miami who studies the El Niño Southern Oscillation ,or ENSO.
Those conditions helped fuel some of the most destructive fires in Los Angeles history. Even 10 months later, the region remains at relatively high risk for fire and in severe drought, according to the U.S. Drought Monitor. Southern California is facing similar drought conditions as it did when the January firestorm broke out, according to the monitor.
Another winter with La Niña could further worsen those conditions, Becker said.
Read more: Rains are soaking Los Angeles for the first time in months. Is it enough to reduce wildfire risks?
“We are probably looking at a weak La Niña, but there have been some studies that have found that second-year La Niñas do have a tendency to enhance already existing drought,” she said.
ENSO shifts don’t guarantee drying, or stronger storms; they only increase the chances for certain climate patterns. But Becker said that warming ocean temperatures caused by human-caused climate change have been magnifying some of the effects of La Niña.
“La Niña is occurring against a background of very warm global oceans and that’s making La Niña behave like it’s stronger than it looks,” Becker said. Even though official La Niña conditions lasted for only a few months last winter, she said, “the whole global atmosphere did look a lot more like La Niña for the whole winter — and we’re expecting a similar type of La Niña [this year].”
NOAA said La Niña conditions had a 55% chance of remaining in place through at least December. The phase could linger even through March.
“Central/SoCal will be favored to be drier than average, but even one or two ‘juicier-than-average’ storms could change that,” Daniel Swain, a UCLA climatologist, wrote in a recent blog post.
Though it’s unlikely to be enough to pull the region out of drought or to ward off concerns of a dry winter, forecasters are expecting an “early season storm” to bring some rainfall to Southern California early next week. Most of urban, coastal Los Angeles, however, won’t see amounts above a half-inch, according to the National Weather Service.
This story originally appeared in Los Angeles Times.
