3 hurricanes in the Pacific show the power of El Niño

Three hurricanes — Karina, Lowell and Marie — are churning in the Pacific Ocean, a high level of activity that climate scientists say is on brand for El Niño, especially given that this year's event is likely to become the strongest on record.

Two of the storms hit major hurricane status this week. Lowell, which could target Hawaii this weekend, reached Category 5 strength Wednesday and has since weakened to Category 3. The storm is moving west but expected to make a sharp turn to the north over the weekend, according to the National Hurricane Center, taking it near the islands of Oahu and Kauai.

The forecast comes as Hawaii is still recovering from multiple instances of heavy rain and flash flooding over the last six months. Just weeks ago, parts of Oahu and the Big Island were hit with intense flooding and strong winds from Tropical Storm Lala. Damage also remains from devastating floods in March, when more than 25 inches of rain fell in some parts of Oahu and more than 19 inches in parts of Maui.

Meanwhile, Karina has weakened from Category 3 to Category 2 east of the Hawaiian islands and is forecast to weaken further over the next 48 hours, according to the hurricane center. Marie, located nearly 400 miles off the coast of Mexico's Baja California Peninsula, is strengthening. The storm could generate strong swells for portions of Mexico's southwestern coast and Baja California through the weekend, and perhaps Southern California, too, according to the hurricane center.

The trio of hurricanes represent a level of elevated activity consistent with El Niño, a natural climate pattern characterized by warmer-than-usual sea surface temperatures in parts of the Pacific Ocean.

This year, the National Oceanic and Atmospheric Administration and other forecasting agencies predict an exceptionally strong El Niño, or "super El Niño," marked by water temperatures at least 2 degrees Celsius (3.6 degrees Fahrenheit) above average in the Pacific.

NOAA's forecast last month suggested that this El Niño event has a 69% chance of becoming the strongest on record.

El Niño typically exacerbates warming from human-caused climate change, further boosting global temperatures and increasing the likelihood of extreme weather.

In El Niño years, the high sea surface temperatures help more Pacific storms to form and grow. Daniel Gilford, a meteorologist and atmospheric scientist at the nonprofit research group Climate Central, likened tropical cyclones to a car engine, with warm ocean water acting like fuel.

"The engine needs some sort of fuel to convert into wind," he said. "If we increase the amount of fuel available to a storm, it's kind of like increasing the speed limit on your car. If we have extra fuel, we can push the accelerator down more and these storms can become more intense as a result."

This El Niño event has taken hold at a time when sea surface temperatures in the Pacific were already significantly elevated. Scientists have been tracking a vast marine heat wave — a prolonged period of unusually high ocean temperatures — in the Pacific that began last year. Gilford said that Climate Central's early studies have found that about 94% of the Pacific has experienced heat wave conditions since January, with some regions already up to 2 degrees Celsius warmer than normal.

"Temperatures across the entire Pacific Ocean are elevated, and we're certainly seeing that in the region where these hurricanes and tropical cyclones are traversing," he said.

In contrast to the flurry of activity in the Pacific, things are relatively quiet in the Atlantic basin — yet another characteristic of El Niño, according to Gilford.

"El Niño conditions change the winds in the atmosphere in such a way that they are not conducive to storms forming in the Atlantic Ocean," he said. "That's exactly what we're seeing right now."

Although El Niño is a natural pattern, climate scientists think it may be intensifying as a result of climate change. A study in the journal Science last month found that El Niño events have strengthened since humans started burning fossil fuels that send heat-trapping greenhouse gases into the atmosphere.

United Nations Secretary-General António Guterres said Thursday that El Niño is "being supersized before our eyes," a situation that should be a call to action.

"The science leaves no room for doubt: the planet is in uncharted waters, and those waters are heating up," Guterres said in response to a new World Meteorological Organization report on the strengthening El Niño. "Sea surface temperatures are rising, temperatures keep climbing, and the world is in the danger zone of extreme weather. The race now is between rising risks and our commitment to take climate action and protect people. We must win that race."

This article was originally published on NBCNews.com