Isaac's Storm - Erik Larson [51]
IN GALVESTON, THURSDAY, Isaac Cline noted in the station’s Daily Journal the presence of scattered clouds and fresh northerly winds. He noted, too, that at 2:59 P.M. 75th meridian time—1:59 Galveston time—he had received an advisory from Washington stating that the tropical storm was now “central over southern Florida.” He saw no cause for concern.
That evening, he climbed to the roof of the Levy Building and recorded a temperature of 90.5, the highest temperature so far that week. The wind, he saw, was from the north at thirteen to fifteen miles per hour. The barometer read 29.818 inches, just a hair lower than the evening before. He saw scattered clouds. The bureau used a ten-point cloud scale, with ten the maximum. He rated the sky at four.
He checked to make sure all the instruments were secure. He walked down to the office, composed a coded telegram to Washington, and gave this to a messenger. Then Isaac walked home.
Squadrons of fat blue dragonflies zigzagged across his path. He nodded to friends and acquaintances, smiled at casual quips about the heat. The horses especially seemed to move more slowly.
Perhaps he felt a mixture of relief and disappointment. The tropical storm was centered over Florida—that meant soon it would cross to the Atlantic, where it would become the concern of other observers in Savannah, Charleston, and Baltimore. He was glad it was gone. Storms brought damage and extra work, and extra work was not something he needed right now.
On the other hand, storms were exciting and gave the bureau a chance to prove its worth. The sight of the red-and-black storm flag raised high over the Levy Building never failed to set Isaac’s heart pounding.
No one ever remembered a nice day. But no one ever forgot the feel of a paralyzed fish, the thud of walnut-sized hail against a horse’s flank, or the way a superheated wind could turn your eyes to burlap.
THE STORM
M Is for Swells
THE HURRICANE HAD begun sculpting the Gulf the moment it left Cuba and now it transmitted storm swells toward Galveston.
Waves form by absorbing energy from the wind. The longer the “fetch,” or the expanse of sea over which the wind can blow without obstruction, the taller a wave gets. The taller it gets, the more efficiently it absorbs additional energy. Generally, its maximum height will equal half the speed of the wind. Thus a wind of 150 miles an hour can produce waves up to 75 feet tall. Other conditions, such as the chance superimposition of two or more waves, can cause waves to grow even bigger. The tallest wave on record was 112 feet, but occurred amid steady winds of only 75 miles an hour.
In a cyclonic system, the wind spirals to the left, but the waves continue forward along their original paths at speeds far faster than the storm’s overall forward velocity. The forward speed of the storm of 1900 was probably no greater than ten miles an hour, but it produced swells that moved at fifty miles an hour, and began reaching the Texas coast fifteen hours after their formation.
Soon after the waves left the cyclone, they changed shape. They retained their energy, but lost much of their height and their jagged crests. They became long, easy undulations, like the grease-smooth swells that Columbus spotted on his first voyage.
As soon as they reached the Texas coast, however, they changed shape again. Whenever a deep-sea swell enters shallow water its leading edge slows. Water piles up behind it. The wave grows again. It is this effect that makes earthquake-spawned tsunamis so deceptive and so deadly. A tsunami travels across the ocean as a small hump of water but at speeds as high as five hundred miles an hour. When it reaches land, it explodes.
GALVESTON
M Is for Heat
CAPT. J. W. SIMMONS, master of the steamship Pensacola, had just as little regard for weather as the Louisiana’s Captain Halsey. He was a veteran of eight hundred trips across the Gulf and commanded a staunch and sturdy ship, a 1,069-ton steel-hulled screw-driven steam freighter built twelve years earlier in West Hartlepool, England,