The National Weather Service declared El Niño has officially arrived, boosting odds for wetter-than-normal conditions in Southern California this winter. Forecasters estimate a 63% chance of a “very strong” El Niño later this year, while scientists and marine
El Niño is already here.
The National Weather Service declared it arrived Thursday. setting in motion a winter forecast that could bring significantly more rain to Southern California. The climate pattern developed over the last month and is expected to strengthen. with the weather service’s Climate Prediction Center putting the odds at 63% for a “very strong” El Niño later this year—one that would rank among the most powerful events on record since 1950.
In a briefing Thursday at the Aquarium of the Pacific in Long Beach, Ariel Cohen, a meteorologist at the weather service’s Oxnard office, said a stronger El Niño would “more significantly tilt the odds towards wetter-than-normal conditions here in Southern California.”
Scientists point to rapid changes in the ocean. Warmer water from the western Pacific Ocean is moving east, and temperatures are increasing deep beneath the ocean’s surface. Those deeper. warmer waters are “the fuel. if you will. for the development and strengthening of the upcoming El Niño event. ” Jon Gottschalck. the Climate Prediction Center’s operational prediction branch chief. said in an interview. That’s why forecasters expect a “potentially a strong-to-very-strong” El Niño—particularly from November through January.
For Southern California, that could mean rain—and potentially a lot of it.
History is one reason officials are paying close attention. Two previous “very strong” El Niños—in 1982-83 and 1997-98—dumped more than 30 inches of rain on downtown Los Angeles. more than double the area’s average annual rainfall. During the winter of 1982-83. damage was especially severe along the coast as high tides surged amid powerful storms. with about $100 million in damage reported. In early 1998. storms brought widespread flooding and mudslides. killing 17 people and causing more than half a billion dollars in damage in California.
Another “very strong” El Niño recently upgraded by scientists, 1991-92, brought 20.86 inches of rain—about 150% of its average annual total—to downtown L.A.
Even when the pattern doesn’t deliver blockbuster rainfall, the impacts can still be severe. The “very strong” El Niño of 2015-16 brought downtown L.A. only about half its annual rainfall, with just 6.88 inches falling, and it failed to end a punishing five-year drought. Yet it still produced “record coastal erosion along many California beaches,” according to the state Coastal Commission.
And rainfall is only part of the story. Cohen said even if the region ends up with a much drier winter, marine interests and people along the coast can still face damaging waves and rip currents.
The weather isn’t the only front. El Niño is one of the most powerful climate patterns on Earth, capable of reshaping global weather and affecting rainfall and drought, according to the World Meteorological Organization. It typically hits every two to seven years and lasts about nine to 12 months.
But “having a stronger. very strong El Niño certainly tips the scale toward a wetter-than-normal year. ” meteorologist Jan Null. an adjunct professor at San José State University. said. “It doesn’t guarantee it.” The meaning for residents is plain: more rain is likely. but it doesn’t automatically translate into more flooding.
The same warming ocean that feeds El Niño can also reshape the marine world beneath the surface. Nate Jaros. the Aquarium of the Pacific’s vice president of animal care for fish and invertebrates. said warmer ocean temperatures may bring an increase in tropical or warm subtropical species. including more shark sightings off the Southern California coast. He added that. in very rare cases. even whale sharks have been seen off Catalina. including during the 2015-2016 El Niño events.
Warmer waters can also increase sea jellies and other gelatinous creatures. Jaros said a jellyfish-like species called Velella velella—also known as by-the-wind sailors—washes up on West Coast shores and is usually harmless. But he pointed to past El Niño events where similar-looking Portuguese man o’ war. a very rare visitor to California waters. has washed up on beaches. “These animals can have a very painful sting,” Jaros said.
Marine heat waves have already taken a toll on kelp forests. Jaros said marine heat waves have decimated California’s bull kelp, with bull kelp habitats declining 90% in Northern California since 2014. He said the effects flow through the ecosystem, including harm to endangered white abalone. Warmer waters can also worsen sea star wasting disease. especially for the sunflower sea star. a population that’s nearly been wiped out of California.
Brett Long. the aquarium’s vice president of animal care for birds and marine mammals. said marine heat waves can be fatal for seabirds when their food disappears. He pointed to knock-on effects like sea lion strandings. “Marine heat wave events often lead to more sea lion strandings,” Long said. “This is because warmer ocean temperatures affect the kind of food available to them. or the production of algal toxins. which can result in severe illness and even death.”.
At the moment, there are currently two marine heat waves unrelated to El Niño near California. One is just off the state’s southern coast that started in December. Another is farther west off the coast of Northern California and Oregon that started in May. according to a map displayed by Andrew Leising. a research oceanographer at the National Oceanic and Atmospheric Administration’s Southwest Fisheries Science Center.
Leising said El Niño also tends to cause marine heat waves. “One of the most important things. though. for the animals in the ecosystem is not necessarily just how hot it is — that is important in some cases — but just how long they’re exposed to the heat. ” he said. He described a situation in Southern California where an existing marine heat wave is already underway and the region may move into “a heat wave that’s been brought about by El Niño as we go into the fall and into next winter.”.
What ties everything together is the timing: El Niño has arrived. strengthening is expected. and the months between November and January are when forecasters say the odds will matter most. Whether the winter turns out wetter—or whether the rain comes up short—the warming pattern is still likely to leave its mark on both coastal weather and ocean life.
El Niño National Weather Service California weather Southern California rain Climate Prediction Center aquarium marine life marine heat waves