La Niña is part of a natural climate cycle that can cause extreme weather across the planet, and its effects vary from place to place.
While there are no guarantees about how this La Niña will play out, some general trends are emerging. According to experts, northern parts of South America could receive more rain than usual. Southern regions of the United States and parts of Mexico may be drier than average. The northern United States and southern Canada may be wetter than average.
See also: It snows in October 2024 in certain areas of Quebec
La Niña is the cold phase of the El Niño Southern Oscillation, a natural global climate pattern that involves changes in winds and ocean temperatures in the Pacific and can cause extreme weather across the planet.
El Niño is the warm phase and occurs when the trade winds that usually blow across the Pacific towards Asia weaken, allowing warm ocean waters to build up along the western edge of South America. South. But during La Niña, trade winds intensify and cold waters from deep seas rise, resulting in colder-than-average ocean temperatures in the eastern Pacific.
These cold ocean temperatures and changes in the atmosphere influence the position of the jet stream ― a narrow band of air moving quickly from west to east around the planet ― moving it northward. The jet stream sits over the ocean and can draw on its moisture, influence the path of storms and increase precipitation.
Recently, Earth experienced a “triple trough” La Niña between 2020 and 2023. “We have experienced three consecutive winters with La Niña conditions, which is unusual because the only other such instance was in 1973-1976,” said Michelle L’Heureux, a climatologist at NOAA. Ms. L’Heureux specifies that La Niña phenomena tend to last longer and be more recurrent than El Niño phenomena.
Ben Cook, a climatologist at NASA’s Goddard Institute for Space Studies, affiliated with Columbia University, said of the forecast of a possible La Niña this year: “It’s unusual, but it’s not is not without precedent.
Mr. Cook noted that the frequency of La Niña events can be stressful for regions that have faced drought in recent times, such as East Africa. “If we are heading into another La Niña, that will mean these very adverse conditions will continue,” he said.
La Niña Weather Impacts
La Niña’s influence on weather conditions varies depending on location and season, Ms. L’Heureux said. Some areas of South America, such as eastern Argentina, may be drier than average, while Colombia, Venezuela, and northern parts of Brazil may be wetter than normal.
“It all depends on where you are. This is partly because Central and South America have a monsoon cycle, a wet season and a dry season, and La Niña changes the intensity and location of these monsoon cycles. monsoon cycles,” explained Ms. L’Heureux.
In the United States, snowfall is difficult to predict and depends heavily on the storm and its track, said Samantha Borisoff, a climatologist at NOAA’s Northeast Regional Climate Center, based at Cornell University.
Ms. Borisoff noted, however, that New England, New York and the Great Lakes region tend to be snowier during La Niña winters, but that’s never a guarantee. Regions of the southern and southeastern United States are further from the active storm path and tend to be drier and warmer than normal.
La Niña, El Niño and climate change
According to scientists, the link between climate change and La Niña and El Niño phenomena is not entirely clear.
Paul Roundy, a climatologist at University at Albany, State University of New York, says climate models tend to indicate that El Niños are more frequent and La Niñas less frequent, but not all models agree. Computer models also have difficulty distinguishing normal variations in El Niño and La Niña phases from the influence of climate change on ocean and atmospheric warming.
“I wouldn’t conclude that climate change isn’t causing more El Niño events,” Roundy said. It’s just that nature itself has such strong fluctuations. So we can have several La Niña episodes, and maybe in 40 or 50 years we will see the opposite.”
Related News :