Posted by The Huffington Post on Friday, October 23, 2015

What You Need to Know

Hurricane Patricia is a whopper. The National Hurricane Center called the Eastern Pacific storm, which is headed toward the coast of southwest Mexico, “potentially catastrophic,” and the sheer numbers associated with it have astonished meteorologists. Eric Blake, a hurricane specialist with the National Hurricane Center, posted a Tweet on Friday stating, “For posterity — 200 mph for a #hurricane — never seen that in modern satellite era!”

And the storm grew still more powerful after that.

What is a Category 5 storm?
This hurricane has reached the most powerful classification of storms on the Saffir-Simpson hurricane intensity scale, Category 5. The scale measures wind speed, while storm surge can cause tremendous damage as well. A Category 5 storm has winds stronger than 155 miles per hour. Such strong winds are associated with catastrophic damage: homes destroyed, trees and power lines felled, and other devastation. After a Category 5, expect the power to be out for weeks, even months; a place that such a storm has blown through is not likely to recover soon. Some scientists have suggested that powerful storms like Patricia are showing the limitations of having just five categories, and that the scale should be expanded.

How did Hurricane Patricia get so powerful so fast?
The storm “exploded,” said Dennis Feltgen, a spokesman for the National Hurricane Center, adding that it currently had the strongest winds and lowest air pressure ever recorded by the agency. “This is one for the record books,” he said. And it’s easy to see why, he said, with its “perfect environment” for rapid intensification, “very warm waters off the coast of Mexico and almost nonexistent wind shear,” or a change in wind direction that tends to blunt the force of a storm.

The speed of its strengthening caught many researchers by surprise, said Kerry A. Emanuel, a professor of atmospheric science at the Massachusetts Institute of Technology. “None of the models we use to forecast intensity, including my own, got this right,” Professor Emanuel said. He suggested that the warm waters of the Pacific, which give energy to storms, might extend to much greater depths than usual, and so the storm’s churning is not bringing up the cold water that often limits the intensity of such storms.

This is a big El Niño year, right? What’s the connection?
El Niño is a complex climate phenomenon that brings warm water to the Pacific, and strong El Niño years tend to be active years for hurricanes in the Pacific (and tend to be lighter years for such storms in the Atlantic). And this is a very strong El Niño year. So it should come as no surprise that the conditions have favored a lot of storms — we are, after all, up to the letter P — some of which are very intense. El Niño is independent of the broader phenomenon known as climate change, which brings us to the next question:

How does climate change come into play here?
No single weather event can be tied to the long-term trend of climate change, but the warming and atmospheric moisture associated with the phenomenon could be expected to bring about conditions that favor powerful storms. Those conditions essentially “raise the speed limit” for storms, Professor Emanuel said, allowing any storm that does develop to potentially build to greater strength. Though most storms do not reach their full potential, Hurricane Patricia appears to be on track to do so.

Is this really the most powerful hurricane ever?
Many experts have called Patricia the strongest hurricane ever recorded. That’s true, as far as it goes, but still might be a bit misleading, Professor Emanuel said. Because the storm threatens to make landfall, it is getting a great deal of attention. “Most of the storms out there just move harmlessly out to sea, and nobody outside of the profession knows about them.” So this particular storm has been measured very carefully and accurately and up close, with instruments like dropwindsondes that simply are not used in many storms. “There’s no question that this — just looking at the satellite imagery and the data — is a very unusual storm,” he said.

Where is the storm heading?
The storm is expected to make landfall in southwestern Mexico near Playa Perula in Jalisco State on Friday. The coast is dotted with fishing villages and beach resorts, including Puerto Vallarta, a popular tourist destination. The nearest major city is Manzanillo, an important shipping port.

How many people could be affected?
According to a 2010 Mexican census, cited by The Associated Press, there were more than 7.3 million inhabitants in Jalisco State and more than 255,000 in the municipality of Puerto Vallarta. More than 650,000 lived in Colima State, and more than 161,000 in Manzanillo.

What is the Mexican government doing to prepare for the storm?
Mexican authorities declared a state of emergency on Friday in the states of Colima, Nayarit and Jalisco, and residents and tourists soon began evacuating coastal areas. Thousands of people crowded bus terminals seeking tickets to Guadalajara and other points inland as airports were closed and roads leading away from the coast were clogged with traffic.