A Pacific cyclone dubbed Polo exploded from a tropical storm into a powerful Category 5 hurricane in less than 24 hours on Tuesday (Sept. 22), with winds reaching speeds of 180 mph (290 km/h). Now drifting off the southwest coast of Mexico, Polo has been downgraded to a Category 4 storm but remains "a very powerful major hurricane," the National Hurricane Center (NHC) said in an update Wednesday (Sept. 23).As Polo moves northwest, it is expected to drive torrential rainfall on parts of Mexico's southwest coast. Although the storm is not predicted to make direct landfall, the NHC has warned that heavy rain may produce life-threatening flooding and mudslides, as well as extremely hazardous ocean conditions.Polo is one of the most powerful storms of the Pacific hurricane season so far, which runs from May to November. But what causes a hurricane like Polo to intensify so rapidly? And what role has the "super" El Niño played in the storm's development?How El Niño contributed "Rapid intensification of tropical cyclones is something we see several times per year across the globe," Julian Heming, an environmental scientist and researcher at the U.K.'s Met Office, told Live Science in an email. "The main requirements are high sea temperatures, low wind shear and upper air conditions which allow air to escape quickly from the top of the hurricane."Hurricane Polo intensified rapidly as it moved over exceptionally warm Pacific waters associated with an extremely strong "super'" El Niño that has taken hold off the Pacific since June. El Niño is a naturally occurring climate pattern that develops in the tropical Pacific Ocean, typically every two to seven years. It begins when waters in the eastern tropical Pacific become unusually warm. The National Oceanic and Atmospheric Administration identifies El Niño conditions when these waters are at least 0.9 degrees Fahrenheit (0.5 degrees Celsius) above average, alongside changes in winds, surface pressure and rainfall that are consistent with the phenomenon. El Niño events are then classified by strength, ranging from weak to very strong. Although "super El Niño" is not a scientific term, it refers to a very strong El Niño, where the warming of sea surface temperatures is higher than 2C above normal.The unusually warm ocean supplied Hurricane Polo with abundant heat and moisture, while very moist air and weak winds higher in the atmosphere allowed thunderstorms to organize and strengthen without being disrupted, Hemming said.Polo also developed a compact, well-defined core, which concentrated the storm's energy into a relatively small area and enabled it to intensify extremely quickly. Together, these conditions created an efficient atmospheric "heat engine" that allowed Polo to strengthen at an exceptional rate.Related storiesHow strong can hurricanes get?'Now is the time': Hurricane category 6 could be introduced under new storm severity scaleBirth of a hurricane: What meteorologists look for as they hunt for early signs of a tropical cyclone forming"Polo's rapid and sudden growth is testament to the dominance of this year's so-called super El Niño, which set a record on Monday as the most extreme on record and has amplified a number of extreme weather events globally," Heming said. The latest data from the World Meteorological Organization suggests that the current El Niño could be the strongest on record and last until at least February 2027. This will lead to more extreme weather, pushing some areas into drought while others experience stronger storms, rainfall and flooding.If the system moves northward, Southern California could see intense rainfall and coastal regions may experience hazardous rip currents and large swells. However, "There is currently a lot of uncertainty in the long term as to whether Polo will move further out to sea or turn north-eastwards towards Mexico," Heming said.

Since 2020, Crescent Island has been cut off from the mainland by rising water. Without predators, animals from wildebeest to giraffe are thriving there, but it isn't all good news.

We know that compact objects can steal cosmic material, and now we are figuring out how.

Antarctic dwellers are wonderfully weird, and it shows in their cells.

Archaeologists excavating a Paris hospital's courtyard, a stone's throw from Notre-Dame, have discovered the first evidence of a Celtic fort that Julius Caesar tried to conquer in 52 B.C. The ancient walls show evidence of a violent fire, seemingly confirming the claim that the Celtic group who lived there, known as the Gauls, burned down their own town so that it wouldn't fall into Caesar's hands."The wall's architecture, with its large blocks and interlocking beam system, immediately led us to believe it was a wall of Gallic tradition," Dorothée Chaoui-Derieux, chief curator of heritage at the Île-de-France Regional Archaeology Service, said in a translated statement. Traces of fire and first century B.C. artifacts further suggested the archaeologists had finally found material evidence of Lutetia, a Celtic settlement mentioned in Caesar's Gallic Wars.In the first century B.C., Lutetia was a Celtic pre-Roman settlement, known as an "oppidum", in what is now Paris. Lutetia was the capital city of the Parisii tribe, who lived along the River Seine. As part of the Gallic Wars, which ran from 58 to 50 B.C., Julius Caesar and his troops fought the Battle of Lutetia in 52 B.C. The Romans won a decisive victory, but the Gauls burned Lutetia and cut the bridges so that Caesar could not take the town. As a result, the ancient fort had never been found.Archaeologists have been working at the excavation site, on the Île-de-la-Cité in Paris, since February 2026. (Image credit: Anastasia Choquet/DRAC Île-de-France)But in February, a team of archaeologists began excavating in the courtyard of the Hôtel-Dieu, which is Paris's oldest working hospital. On the small Île-de-la-Cité island in the middle of the Seine, close to Notre-Dame, the archaeologists discovered a 65-foot (20-meters) stone and timber wall typical of Celtic fortifications. Charred facing, burnt seeds and a burned wooden building discovered nearby suggested the site had been destroyed by a fire. "The initial results of carbon-14 dating of the wooden elements suggest a date range between 200 and 10 B.C. Furthermore, a Gallic spearhead was found at the foot of the wall," Chaoui-Derieux said. RELATED STORIESDid Celtic women fight in battle?2,000-year-old Celtic teenager may have been sacrificed and considered 'disposable'5 'extremely rare' iron shackles discovered in France highlight Celtic slave trade 2,300 years agoThese new discoveries provide solid archaeological evidence that Lutetia was indeed centered on the island in the Seine and that its occupants burned it down, as Caesar noted in his Gallic Wars more than two millennia ago. "This discovery fills an archaeological gap. For centuries, the location of Lutetia has been debated," Stéphane Deschamps, regional curator of archaeology at Île-de-France Regional Archaeology Service, said in the statement. "Today, with this wall and its context, we may hold the key to the mystery."But the remains of the wall and other artifacts are extremely fragile because of their exposure to fire, according to the statement. The wall cannot be fully preserved, so archaeologists will create a replica using 3D photogrammetry to ensure the discovery is accessible to everyone.See how much you know about the Celts with our Celtic quiz!