Читать книгу Into the Raging Sea - Rachel Slade - Страница 16

A hurricane is not a point on a map.

It is not an object that exists in space and time. Rather, it’s a huge catharsis—a brief, explosive event when nature’s forces combine to spin off the ocean’s heat into wind. Over its brief life span, a hurricane expends the power of ten thousand nuclear bombs. It’s a spectacular display of thermodynamics in a complex, evolving, moving system.

Like a cancer, a hurricane is a lethal distortion of the stuff of everyday life. The earth’s winds harmlessly swirl about us, creating patterns in the clouds, kicking up waves for surfers, and nudging planes around the planet. All these heavenly movements are tendrils of much larger systems, like the jet streams that forever flow east, caught up in the rotation of Earth. Thanks to the jet stream, winter storms always pound New England in February when arctic air from Canada drifts south over the plains, gets swept east in its current, and is carried to the warmer air over the Atlantic Ocean.

Although the earth’s meteorological picture is as vast as the planet itself, it is very sensitive, prone to disruption, fickle. A butterfly-wing-like change in pressure or temperature in one place can cause a small piece of the continuum to break away from the mainstream like a recalcitrant teen. It often fades into the ether. But sometimes, when conditions are right, it can escalate exponentially, causing astounding damage to anything in its path.

Perhaps to domesticate these mighty systems, we give them names—Katrina, Sandy, Mitch, Joaquin. We mark them on our maps and say this is where she is. We draw a line and say this is where he will go. As if one day, a storm named Katrina rose out of the Gulf of Mexico like a Japanese monster hell-bent on ravaging New Orleans. As if you could put a beacon on her and track her every move as she made her way to her target. As if there were some kind of motive behind the destruction.

TROPICAL DEPRESSION ELEVEN FORECAST/ADVISORY NUMBER 1: 0300 UTC MON SEP 28 2015: TROPICAL DEPRESSION CENTER LOCATED NEAR 27.5N 68.7W AT 28/0300Z. PRESENT MOVEMENT TOWARD THE NORTHWEST AT 2 KT. MAX SUSTAINED WINDS 30 KT WITH GUSTS TO 40 KT.

Every hurricane begins as an atmospheric low, or depression, in the bottom layer of the earth’s atmosphere—the troposphere—which reaches up to seven miles above the planet’s surface. The low acts like a vacuum, pulling up warm, moist air from the ocean, which spirals around it in a counterclockwise direction in the Northern Hemisphere. If conditions are right—plentiful warm, humid air—the currents corkscrew upward around the low pressure zone at increasing speeds. When that heated air hits the much cooler upper atmosphere, it condenses, shooting out of the hurricane’s top like a whale’s spout, away from the center, and falls to earth as rain.

Feeding on the temperature and humidity differential between the hot ocean and the chilly upper atmosphere, the tropical storm thrives. Air currents around the center pick up heat, and with it, speed, as the center’s pressure drops even lower, intensifying the cycle. “Warmest climes but nurse the cruellest fangs,” wrote Herman Melville.

Joaquin was born as a tropical depression off the Canary Islands, three thousand miles east of Puerto Rico, a birthplace strange and rare for tropical cyclones because it was so far north. Designated Tropical Depression Eleven, it remained a loose cluster of showers that meandered across the North Atlantic toward the Caribbean. Forecasters at the National Hurricane Center in Miami ran their computer models and concluded that the system would dissipate. Over the course of a few weeks that September, however, Eleven defied the odds to become a cohesive system.

Even as Joaquin matured, dozens of computer models at the NHC in Miami predicted its demise. Some didn’t, but they were dismissed as outliers. On Monday, September 28, the day before El Faro departed from Jacksonville, the NHC issued an advisory: “The forecast for T.D. Eleven is to maintain tropical depression status while drifting slowly NW and will likely dissipate by the end of the week due to unfavorable winds aloft.” When Joaquin failed to comply, it took NHC forecasters by surprise.

In spite of a moderate shear—competing crosswinds that most forecasts predicted would blow it apart—at midnight on September 29, Eleven evolved into Tropical Storm Joaquin.

TROPICAL STORM JOAQUIN/ADVISORY NUMBER 6: 0900 UTC TUE SEP 29 2015: TROPICAL STORM CENTER LOCATED NEAR 26.6N 70.6W AT 29/0900Z. PRESENT MOVEMENT TOWARD THE WEST AT 4 KT. MAX SUSTAINED WINDS 35 KT WITH GUSTS TO 45 KT.

Throughout Joaquin’s evolution from depression to hurricane, the NHC could only guess at how it would develop, and what path it would take. The center issued discussions—carefully worded explanations of its forecasts of the storm system’s path and intensity. Embedded within these discussions were clear admissions of ambivalence: “There is considerable uncertainty among major models with the details of track . . . intensity and timing not only of Joaquin, but also the surrounding environment,” the center wrote at 2:47 p.m. EDT on Tuesday, September 29.

The same uncertainty was included in its weather discussion issued thirteen hours later.

Uncertainty in forecasting can be quantified. When models contradict one another, uncertainty is expressed as a probability.

In the course of everyday life, we don’t often encounter uncertainty. Gamblers and hedge funders may weigh odds all day, but most of us aren’t sure what to do if someone says she’s 30 percent sure she’s wrong. How do you process that, especially in a world where so many decisions are made for us by technology?

“If the definition of wisdom is understanding the depths of your own ignorance, meteorologists are wise,” says Kerry Emanuel, an MIT professor who has dedicated his life to understanding weather and climate. “It’s wise but it’s a wisdom that is not recognized. If you say there’s a lot of uncertainty in this, in the modern world, it’s translated as You don’t know anything.”

Due to uncertainty, prudent mariners follow the 3-2-1 rule: Three days ahead of a hurricane’s forecasted position, stay three hundred miles away; two days ahead, keep out of a two-hundred-mile radius of its projected center; one day ahead, stay one hundred miles away from its eye in all directions. The rule is based on the fact that hurricane paths are erratic and unpredictable, so it’s smart to give the system a wide berth.

But mariners often need to make binary decisions based on nebulous weather forecasts. On October 24, 1998, the elegant Fantome, a 679-ton staysail schooner built in 1927, departed Honduras for a six-day Windjammer cruise. A thousand miles away, Hurricane Mitch rumbled in the Caribbean Sea. As Mitch picked up strength, the captain of the Fantome got nervous and discharged his passengers in Belize City, then headed north toward the Gulf of Mexico to outrun the storm.

Forecasting Mitch proved extremely difficult due to weak steering winds, but the official NHC prediction, issued with multiple caveats, was that the storm would go north toward Mexico’s Yucatan Peninsula. When the Fantome’s captain received that forecast, he hove to and headed south, unwittingly right into the hurricane’s path, which, contrary to forecasts, took a left turn toward Central America. On October 27, fighting hundred-mile-per-hour winds and forty-foot seas, the Fantome was lost forty miles south of the hurricane’s deadly eye wall.

Slow and unyielding, the Category 5 storm’s winds and rains killed more than eleven thousand people in Honduras, Nicaragua, El Salvador, and Guatemala, making it the second-deadliest storm in the Atlantic’s history.

HURRICANE JOAQUIN FORECAST/ADVISORY NUMBER 11: 1500 UTC WED SEP 30 2015: HURRICANE CENTER LOCATED NEAR 24.7N 72.6W AT 30/1500Z. PRESENT MOVEMENT TOWARD THE SOUTHWEST AT 5 KT. MAX SUSTAINED WINDS 70 KT WITH GUSTS TO 85 KT.

Weak, meandering, dispersed Joaquin was precisely the kind of storm the NHC has trouble forecasting, says James Franklin, director of the center, as we sit in his Miami office a year and a half later. James has two MIT degrees, rimless glasses, and a quiet, analytical manner. He speaks in complete paragraphs. But his quiet demeanor belies an intrepid soul. James used to fly in NOAA Hurricane Hunters, straight into tropical storms. The Gulfstream IV is a high-altitude jet that flies in and around hurricanes recording conditions and dropping sondes (disposable devices outfitted with a parachute) that gather critical data about the storms as they fall from the sky. The planes often ride hurricane updrafts, and then on the very inside edge of the eye wall where the air all rushes down, plummet more than nine hundred feet.

“Have you ever been on the Tower of Terror ride at Disney?” he asks me. “It’s basically a big elevator where you get dropped. So it’s sort of like that. I did that for seventeen years.”

Joaquin just didn’t look like it meant business, until it did. “By getting the intensity forecast wrong,” James says, “that contributed to our getting the track forecast wrong. If we had correctly anticipated that Joaquin was going to beat the shear and remain a stronger storm, that would have argued for a forecast more to the south.”

James explains why even with advanced computers and significant amounts of data, we still can’t accurately predict the future 100 percent of the time. In fact, an important part of the NHC meteorologists’ job is to keep tabs of, and learn from, error. The NHC is one of the few government offices that obsessively tracks its own mistakes; meteorologists use these errors to improve their models and methods.

On the NHC website, there’s an entire section dedicated to its own errors going back to 1970. Multiple line graphs detail two kinds of errors: track errors and intensity errors. What path the storm takes depends on the larger forces around it. Like a leaf floating down a powerful river, it can get caught in swirling eddies, loop back, cut loose, and stall in slower currents near the riverbank. Meteorologists often think of weather systems in terms of fluid dynamics. But unlike a leaf, the hurricane is a nine-mile-high engine—making its movements and behavior even more difficult to predict.

Heat is the fuel that drives the hurricane’s engine. The more heat the system absorbs into the upper atmosphere from the warm waters below, the faster it spins, converting the heat’s energy into powerful winds. That’s why hurricanes in the Northern Hemisphere occur late in the season, after the summer sun has warmed the southwestern Atlantic up to 84 degrees.

As oceans continue to warm due to climate change, hurricanes will get more intense because they’ve got more fuel to convert to energy. We’ve already witnessed proof of this; several tropical cyclones have broken records in the past decade alone. Hurricane Sandy, which pounded the New Jersey and New York coasts in October 2012, was the largest Atlantic hurricane on record, spanning eleven hundred miles. A year later, Typhoon Haiyan in the Philippines became the strongest tropical cyclone to hit land ever recorded, with one-minute sustained winds recorded at an astounding 195 miles per hour, killing at least sixty-three hundred people. Hurricane Patricia intensified at an unprecedented rate off the western coast of Mexico two years later, churning out record-breaking maximum sustained winds of 215 miles per hour.

Hurricane Irma, followed by Hurricane Maria, revealed exactly how destructive these systems can be. The huge Category 5 hurricane blasted through Puerto Rico on September 20, 2017. Its tornado-like winds knocked out the entire power grid and nearly all cell-phone infrastructure and cut a swath of devastation, peeling off roofs, stripping away all vegetation, and causing widespread flooding. Ports were closed, and much of Puerto Rico’s shipping infrastructure was compromised by winds and flooding.

In the aftermath, Puerto Ricans found themselves without fresh food, water, and electricity. Hospitals, schools, homes, and factories went dark. Some towns were completely wiped out. Tankers were unable to dock or unload; without fuel, emergency efforts ground to a halt. By mid-October, more than 1.2 million people on the island lacked access to potable water.

HURRICANE JOAQUIN FORECAST/ADVISORY NUMBER 13: 0300 UTC THU OCT 01 2015: HURRICANE CENTER LOCATED NEAR 23.8N 73.1W AT 01/0300Z. PRESENT MOVEMENT TOWARD THE SOUTHWEST AT 5 KT. MAX SUSTAINED WINDS 100 KT WITH GUSTS TO 120 KT.

Joaquin would continue this superheated superstorm trend with its own series of unprecedented stats. As it was forming, it traveled westward, but a ridge of high pressure blocked its forward progression, redirecting it south over the hot Bahamian waters—about 86 degrees—two degrees hotter than ever recorded at that time of year. This was the heat Joaquin needed to thrive. For sixty hours, the storm fed off these warm waters and rapidly intensified. At 2 a.m. on September 30, about 170 miles east-northeast of the small Bahamian island of San Salvador, Joaquin became a hurricane.

Mariners live and die by weather. Naturally, they are obsessed with forecasts, signs, and augurs. Long after a seaman has turned his back on the ocean, he follows the weather. He might live in landlocked New Mexico, four hundred miles from the nearest boat, but he’ll still be able to tell you all about the system forming off the coast of the Bahamas.

At home in Portland, Maine, on September 29, 2015, El Faro’s off-duty Second Mate Charlie Baird couldn’t pull himself away from the Weather Channel. He’d just stepped off El Faro a week before, relieved by Second Mate Danielle Randolph. The pair had been tag-teaming the job for a couple of years, seventy days on, seventy days off. Now he was on his sofa, still in his robe at ten o’clock in the morning. He didn’t like what he was seeing, this storm developing in the Atlantic. He was off the clock, but he couldn’t help himself.

He picked up his phone and texted El Faro’s captain, Michael Davidson: “Storm forming north of the bahamas!!”

Growing up in Portland, Charlie loved the water, loved sailing, loved the sea. In high school, he was a state-champion swimmer, breaking record after record, and got recruited to swim at Niagara College. At sixty-six, he’s still remarkably fit, and still competing in triathlons. A handful of medals hang from the chandelier in his dining room.

Charlie joined the merchant marine in the early ’80s. He’s been shipping so long that, like many mariners, he’s missed a lot of life while at sea. Like someone who’s spent a few years in a coma, he’s kind of disconnected. A lot of casual conversation doesn’t make sense to him—movies, music, and events have simply passed him by. He would make a terrible Trivial Pursuit partner.

Charlie lets this all wash over him as he swigs another glass of red wine on ice.

He knew not to mess with hurricanes. First, there are the winds. At low speeds, the wind’s force on a large ship is minimal. That is, up to about 35 miles per hour. Wind speed and force have an exponential relationship, meaning that as the wind notches up, its force doubles, then triples, and then quadruples, and so on. It’s based on a simple formula: wind pressure per square foot = 0.00256 x (wind speed)². Put another way, between 1 mile per hour and 35 miles per hour, the wind’s force against the boat runs roughly six to nine times its velocity. That’s the kind of incremental change that the human brain can handle. But over the next 35 miles per hour, its force rapidly grows to eighteen times its velocity. At 112 miles per hour, the wind’s force is thirty times its velocity—you can’t stand upright in that kind of wind no matter how far you lean; first you’ll slide across the ground, then you’ll get thrown backward into an uncontrollable somersault.

This power makes a big difference when you’ve got a crosswind across a large surface area, say, like the side of a container ship piled with boxes. At midspeeds, the wind’s force would be equivalent to twenty-one tons pushing up against that ship. You’ll heel a bit, and might want to shift your ballast to try to correct. Ratchet up the wind’s velocity to 110 miles per hour, and you’ve got about 375 tons trying to push the ship over. That’s the cumulative force of three of the world’s largest locomotives. If you’ve got vulnerabilities, like a low deck with lots of openings, that kind of force can be catastrophic.

And then there are the waves. At first, the cyclone’s high winds cause whitecaps to form on the water’s surface. As the hours pass, the waves grow. Start with a completely calm sea at noon on Monday; a 28-mile-per-hour wind starts to blow and by 11 p.m. on Tuesday, you’ll have thirteen-foot waves. A rough guide for wind to wave height is two to one—60-mile-per-hour winds (52 knots) stir up thirty-plus-foot waves, depending on fetch, or the length of open water over which the wind blows.

Of course, most mariners hope they’re never caught in seas like that, especially in a small boat.

How big can ocean waves get? For millennia, sailors spun stories about extreme waves a hundred feet high that came out of nowhere and smashed apart boats with just one hit. These were dismissed as salty tales, like mermaids and sea monsters. Even in the modern era, scientists considered freak waves a physical impossibility, in spite of compelling evidence to the contrary. During World War II, a rogue wave nearly sunk the Queen Mary ocean liner. The thousand-foot-long luxury passenger ship had been stripped down to carry American troops to Europe, and in December 1942, it was loaded with more than sixteen thousand American soldiers when a ninety-foot-high wave smacked her broadside, causing the ship to roll 52 degrees. There were plenty of witnesses to vouch for that one.

It wasn’t until modern equipment began recording rogue waves that scientists finally acknowledged their existence. On January 1, 1995, a laser aboard an oil rig in the North Sea recorded an eighty-four-foot-high wave. Since then sea buoys, satellites, mariners, and passengers have recorded these waves, confirming that indeed, they’re no myth.

Twenty-two minutes after Charlie texted him about Joaquin, Davidson texted back: “yup . . . thx for the heads up.”

Charlie sat on that sofa all day, watching the weather.

Monitoring the storm was the second mate’s job.

Danielle should’ve been obsessing about it just like him.

Charlie knew she wasn’t. He was fond of his fellow Mainer, a perky, freckled redhead half his age. He’d taken her under his wing like a little sister a decade ago when she joined the company while a cadet at Maine Maritime Academy. Back then, she was all energy, but ten years of shipping was wearing her down. Danielle recently found out she’d been passed over for a promotion to the new LNG ships. That killed what was left of her enthusiasm for her shipping career, and now he thought she was clocking in, clocking out.

Basic tasks seemed to elude her, like correctly plotting the ship’s location during her watch. She didn’t actively seek extra work to keep things running smoothly on the decrepit ship. Why bother? TOTE had kicked her to the curb after she’d sacrificed so much of her life to this career. Danielle started taking over-the-counter meds to fall asleep during her breaks and slamming caffeine to stay awake during her watch. These days, she went unusually quiet when her closest friends in Maine asked her about her life at sea.

And there was more. As Charlie was preparing to leave the ship to go home this last time, Danielle pulled him into her cabin and told him something about Captain Davidson he didn’t want to hear.

There was no way she was thinking about weather.

But Charlie was.

He couldn’t take it anymore. At 6:31 p.m., he texted Davidson again: “Whats your plan?”

“we’ll steam our normal direct route to SJP,” Davidson texted back a few minutes before 7:00. “no real weather to speak of until the evening of the 30th. all forecasted information indicates Joaquin will remain north of us and by the morning of the 01st we will be on the backside of her. we schedule to depart the dock at 20:00 tonight so everything is shaping up in our favor.”

“Cool if u have to we have routes thru mauagiez crooked isle or ne prov chnl,” Charlie reminded him. This was shorthand for the channels between the islands along the way deep enough that El Faro could use them as escape routes to the lee side if anything should brew up out there.

“Watchin sox presently up 1-0 over ny,” he wrote.

“2-0 sox,” Charlie added a few minutes later.

“go sox . . .” Davidson replied.