Isaac's Storm - Erik Larson [49]
Wave after wave washed the ship’s deck and thundered against the cabin ports. By now all thirty passengers were sick beyond fear. At one point a giant wave struck the ship from behind just as it slid into a valley between two other mountains of water. In an instant, the ship was buried bow to stern under tons of green sea and foam.
The Louisiana rose clear, her deck like the rim of Niagara Falls. Another wave caught the ship broadside and flushed seawater down her ventilation shafts into the engine room.
It was at this point that Halsey estimated the velocity of the wind at 150 miles an hour.
THE TRANSFORMATION WAS stunning: One moment a nondescript tropical storm, the next, a hurricane of an intensity no American alive had ever experienced. The storm did not grow through some gradual accretion of power; it exploded forth like something escaping from a cage. The Weather Bureau of 1900 had a code word for winds of 150 miles an hour—extreme—but no one in the bureau seriously expected to use it.
The storm had undergone an intensification known to late-twentieth-century hurricanologists as explosive deepening, but the Weather Bureau of Isaac’s time had no idea such a dramatic change could occur. As the twentieth century closed, hurricane experts still did not understand what caused it. There were theories, however. For a storm to grow so quickly, some researchers proposed, it had to encounter an additional atmospheric force—an upper-level vortex, perhaps, or a fast air-stream that somehow set the storm spinning more and more rapidly. Hugh Willoughby, head of the National Oceanic and Atmospheric Administration’s (NOAA’s) Hurricane Research Division, proposed that explosive deepening could be caused when a storm passed over the Loop Current, a branch of the Gulf Stream that propels warm water through the Straits of Florida.
The Loop may have been in place in the summer of 1900. The Gulf was hot to begin with because of ambient high temperatures and because so far in that season there had been no other hurricanes to roil and cool the waters. The Loop brought a deep channel of warmth that the wind and rough seas could not have cooled. If present, it would have been directly in the path of the storm of 1900 when it exited Cuba. “If a storm runs over the Loop,” Willoughby said, “it’s got essentially an infinite source of heat.”
No one knows whether crossing the Loop triggered the storm’s electric growth. What is certain, however, is that for the storm to have generated winds of the velocity reported by the Louisiana’s Captain Halsey, it had to have formed an open, circular core of extremely low pressure. Isaac and his peers in the Weather Bureau preferred to call this the focus, or center. They shunned the term eye, coined by the Spanish and used so freely by Spanish captains. It was too romantic, too anthropomorphic. In the age of scientific certainty, one could not allow one’s judgment to be clouded by mere poetry.
AT THE VERY center of the eye, the air is often utterly calm. Sailors throughout history have reported seeing stars at night, blue sky during the day. Often, however, the eye is neither clear nor cloudy, but filled with a liquid light that amplifies the stillness, as if the world were suddenly fused in wax. The sea, however, is anything but calm. Freed abruptly from the wind, waves from all quadrants of the eyewall converge at the center, where they collide and compound to form sudden mountains of undirected energy.
Sunlight playing in the eyes of cyclones produced colors that drove brave seamen to their knees. Captains reported olive-green clouds and a spectral blue light that stained sails and the faces of men until all seemed turned to ice. In 1912, the Reverend J. J. Williams of Black River,