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Scientists monitor Patricia as it storms inland

A monster at sea, Hurricane Patricia quickly lost power after it made landfall in the Mexican state of Jalisco yesterday evening. The winds of the Category 5 storm had fallen from a maximum of 200 miles per hour (322 kph) to 165 mph as it came ashore near the resort town of Cuixmala just after 6 p.m. local time. By 10 p.m. Patricia had been downgraded to a Category 4 hurricane, and it continued to lose power overnight as it hit the mountains of the Sierra Madre Occidental range. By 9 a.m. on Saturday, Patricia was a tropical storm. It is expected to continue its northeasterly sweep across Mexico and into Texas, causing heavy rains through the weekend. As of Saturday afternoon, no fatalities had been reported.

Patricia had intensified quickly over the eastern Pacific, leaving local residents and Mexican authorities little time to prepare for a storm the National Hurricane Center in Miami, Florida, called “potentially catastrophic.” In a statement on Friday night, Mexican president Enrique Peña Nieto said that more than 1000 shelters had been set up through the affected region. He encouraged residents to remain in the shelters even after the strongest winds had passed, because heavy rains still pose a risk. “We’ve had the active participation of those who live in the high-risk zones,” he said, thanking residents for following evacuation and preparation instructions.

“It’s a surprise” that Patricia didn’t cause more damage in the coastal areas where it hit, says Luis Manuel Farfán Molina, a hurricane researcher at the La Paz campus of the Center for Scientific Investigation and Higher Education at Ensenada in Baja California Sur. But he cautions that the full picture of the storm’s effects is still forming. Patricia hit at the end of Mexico’s rainy season, and the already wet ground in the mountains may be particularly susceptible to coming loose in mudslides. “That could be happening now,” says Farfán. “It takes a little while to know” what the situation is on the ground, especially if the storm damaged internet and electricity infrastructure. When Hurricane Manuel hit Mexico’s west cost in 2013, over 100 people died in mudslides and flooding.

Patricia was the strongest hurricane ever recorded—but perhaps not the strongest ever to form in the eastern Pacific, says Kerry Emanuel, a meteorologist at the Massachusetts Institute of Technology in Cambridge. Tropical cyclones in that region rarely threaten land, so NOAA’s Hurricane Hunter airplanes aren’t often dispatched to study them. Patricia, however, was carefully monitored by the National Hurricane Center, the National Oceanic and Atmospheric Administration (NOAA), and NASA, generating valuable data and giving scientists around the world “a good opportunity to study the interior” of an extremely strong and quickly intensifying storm, Farfán says.

Hurricane Patricia was also studied by the WB-57, an old Navy bomber retrofitted for scientific research by NASA. Unlike hurricane hunters, which fly through storms, the bomber flew above it, at altitudes above 18,000 meters, studying Patricia’s interactions with the lower stratosphere and dropping instrument packages into the storm, Emanuel says. “We’ve never been able to measure the upper third or so of a hurricane,” Emanuel says.  “I think we’re going to learn a lot from that.”

Patricia formed during a particularly active hurricane season. “This year we’ve broken all the records for the number of Category 4 and 5 hurricanes and typhoons in the northern hemisphere,” Emanuel says. Patricia’s appears to have gained strength from this year’s El Niño event, which swept warm water—fuel for tropical storms—into the eastern Pacific. Climate change is expected to increase the number of strong storms over the next century, but so far scientists haven’t observed any increasing trend in the eastern Pacific.

Figuring out what Patricia has in common with other strong tropical storms is high on researchers’ agendas. Each individual storm has “[its] own particular story,” says Thomas Knutson, a climate modeler at NOAA’s Geophysical Fluid Dynamics Laboratory in Princeton, New Jersey. But when you look at enough extremely strong hurricanes, “there may be some things that tie them together,” says Knutson’s colleague Gabriel Vecchi. For example, it appears that both Hurricane and Patricia and Typhoon Haiyan, which killed 6000 people when it struck the Philippines in 2014, bulked up by drawing energy from unusually deep layers of warm water in the Pacific.

Now, scientists are waiting to see what will happen when Patricia meets a low-pressure front currently forming in the Gulf of Mexico. The interplay of those two weather systems “could lead to big impacts,” including severe floods, Vecchi says. So although Mexico’s west coast may have gotten off lightly, trouble might be on its way to the Mexican and U.S. Gulf states. “We can’t let our guard down yet,” President Peña Nieto says.