It’s been an intense hurricane season in the Pacific

Tropical storms have spawned in the Pacific in what seems like assembly-line fashion in recent weeks, as El Niño conditions that emerged in June have caused waters to grow warmer than normal, setting off a chain of unusual weather around much of the world.

“It’s ramping up to be perhaps the strongest El Niño on record,” University of Miami hurricane expert Brian McNoldy said.

The number of hurricanes in the eastern Pacific has already surpassed what occurs in a typical season. This week alone, Hurricane Polo drenched Mexico’s Pacific coast as it seesaws between Category 4 and 5. And in storm-weary Hawaii, there’s the potential for catastrophic flooding from a growing Hurricane Nolo.

During El Niño, low-level surface winds blowing from east to west across the Pacific are weakened or sometimes reversed. It causes a shift in the jet stream and drives record global heat, severe droughts, wildfires and shrinking water supplies.

El Niños don’t follow a regular schedule, occurring every two to seven years on average. Some can be mild. Others can pack a punch. McNoldy predicted that the current El Niño will peak during the coming winter but linger into 2027.

“It doesn’t turn off right away,” he said.

While the focus is on the increased number of Pacific storms, El Niños conversely curtail hurricane activity in the Atlantic Ocean: Tropical weather activity in the Atlantic has been virtually silent this year.

A turbocharged hurricane year in the Pacific

Thanks to El Niño, both the eastern Pacific and the central Pacific have seen four more tropical storms than is normal to date with more than two months left in the hurricane season, said Matthew Rosencrans, lead hurricane season forecaster with NOAA’s National Weather Service.

From 1991 to 2020, there was an average of 15 named storms in the eastern Pacific per season, which runs from May 15 to November 30.

But surpassing the yearly average in September?

“That’s a different story,” Rosencrans said.

What also sets this year’s El Niño-fueled storms apart is that three Pacific hurricanes have reached Category 5 strength, tying a record set in 2002, also during an El Niño, he said.

The most active season on record in the eastern Pacific was 1992, when there were 25 named storms, Rosencrans said. For the central Pacific, it was 14 in 2015.

In 2015, there were nine major hurricanes, of Category 3 or higher, in the eastern Pacific, but no reported deaths. Due to El Niño, forecasters said the eastern Pacific storms formed farther west and tracked more westward, remaining over the open ocean throughout their cycle.

During another strong El Niño in 1997, hundreds of people died when Hurricane Pauline tore across Mexico’s Pacific coast. That same year Tropical Storm Nora gave landlocked southwestern Arizona an unusual soaking. And a December storm in Southern California caused flooding that swept cars into a storm channel and prompted evacuations of some mobile home parks.

In 1998, El Niño was blamed for flooding in China that killed 4,150 people, most along the Yangtze River.

The Associated Press