This year’s El Niño global weather phenomenon has tied a mark set in 1997 as the strongest on record, with sea-surface temperatures in the equatorial Pacific Ocean set at 2.3 degrees Celsius above average.
The National Oceanic and Atmospheric Administration (NOAA) Climate Predication Center released data on Monday that looked at surface temperatures from October through December 2015.
Mike Halpert, NOAA deputy director, said the El Niño influences weather and climate patterns by affecting the position of the Pacific jet stream, which in part explains why this year has been “wet in California and the southern parts of the US and generally warmer in part of the northern US.”
“El Niño kind of shapes the circulation and the background flow,” he says, in a telephone interview with The Christian Science Monitor on Wednesday. “Really the message is that the ocean is significantly warmer than usual.”
During the same period in 1982, another El Niño year, average temperatures were 2.1 degrees above average, nearly equaling the records set in 1997 and 2015. The federal government began recording El Niño trends in 1950.
El Niños are triggered when Pacific Ocean winds reverse direction or fade, leading to warmer waters and a change in the jet stream, according to NOAA.
But El Niño is not the only dynamic influencing this season’s temperatures, Halpert said. Arctic oscillation can affect air masses on the US east coast and in the south.
“What goes on over the Pacific plays a larger role over America,” he says, also noting that global warming is a factor as well. “The planet is a little different than it was 18 years ago."
“All of these events while they’re unique I suspect they do have a lot of commonalties," he adds.
El Niño generally brings heavy rains to California, an occurrence that has picked up in recent weeks in the state. Up to 15 inches of rain may fall in parts there in the next two weeks, bringing much-needed water to the drought-stricken region, along with concern over floods and mudslides.
Storms killed 17 people between the end of 1997 and early 1998, the last robust El Niño season.
This year's El Niño has also caused tumultuous conditions in much of the United States, with record-setting winter temperatures across much of the country and deadly storms and flooding in significant portions of the South and Midwest.
According to NASA's Jet Propulsion Laboratory, more inclement weather may be on its way.
Last month, the governmental organization used satellite imagery to document high sea surface heights in the central and eastern Pacific Ocean, a phenomenon that normally happens when warmer ocean temperatures occur. The finding also show that “weather chaos” is taking place around the world.
"The El Niño weather system could leave tens of millions of people facing hunger, water shortages and disease next year if early action isn't taken to prepare vulnerable people from its effects," aid agency Oxfam International warned in a press release, according to NBC News.
Next week, NOAA will release its forecast for the upcoming season.
“We’ll start to look at the future evolution of this event,” Halpert says, referring to the current El Niño.