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Hurricane Patricia quickly grew into a Category 5 storm as it headed for the west coast of Mexico.

UW/CIMSS/William Straka III

Patricia’s intensity catches scientists off guard

MEXICO CITY—Stunning scientists with the speed of its intensification, Hurricane Patricia, the strongest storm ever recorded in the eastern Pacific, made landfall on the west coast of Mexico this evening. A Category 5 hurricane, Patricia contains maximum sustained winds of 200 miles per hour (322 km) with even stronger gusts. The storm came ashore just north of Manzanillo, a major port in the state of Colima. “It is an extremely dangerous hurricane and is expected to be catastrophic,” said Roberto Ramírez de la Parra, Director General of Mexico’s National Water Commission (CONAGUA), in a press conference this afternoon.

Patricia developed from a Category 1 to a Category 5 hurricane in just one day. “We all knew, because the conditions were pretty good for hurricanes, that this storm would intensify rapidly,” says Kerry Emanuel, a meteorologist who studies hurricanes at the Massachusetts Institute of Technology in Cambridge. “But nobody knew it would get this intense. The computer models that we rely on, including my own, didn’t even get close to the measured intensity of the storm.”

There are a few possible reasons for Patricia’s unprecedented strength, says Gabriel Vecchi, an oceanographer at the National Oceanic and Atmospheric Administration’s Geophysical Fluid Dynamics Laboratory in Princeton, New Jersey. “There are a lot of indications that there’s a deep layer of warm water extending off the west coast of Mexico right now,” he says. Hurricanes power up their circulation by evaporating warm water from the ocean, but usually that process eventually brings enough cold water to the surface to weaken the storm. That didn’t happen with Patricia. The warm layer in the eastern Pacific is currently about 180 feet deep, “about three times normal for that region,” Emanuel says. The abundance of warm water feeding Patricia might be an effect of this year’s strong El Niño event. Other, longer climatic cycles are also at points that favor warmer conditions in the eastern Pacific, Vecchi says. Patricia “just had everything going for it,” agrees Emanuel.

Due the effects of climate change, the eastern Pacific is expected to see more and higher intensity storms by the end of this century, says Thomas Knutson, also of NOAA’s Princeton lab. He recently published a paper in the Journal of Climate that predicts an 8% increase in wind speed intensity in eastern Pacific hurricanes over the next century. The number of days when the region is experiencing Category 4 or 5 storms will increase by 500%, Knutson says. So far, however, this trend has not been observed.

Soon after making landfall, Patricia was expected to collide with the Sierra Madre Occidental, a high mountain range running down Mexico’s west coast. That will likely cause the high speed winds to dissipate, but rains will continue. “Once it goes inland, the big threat is flash floods from torrential rains,” Emanuel says. “That’s no joke.” Mudslides could also be fatal in the mountainous region.

CONAGUA director Ramírez said the agency is monitoring a cold front currently moving from Texas into northern Mexico. The interaction between it and the hurricane system may cause heavy rains and flash floods all over the north of Mexico, potentially reaching as far north as Texas.