Science: Out of the Doldrums

Australians call it willy-willy; Filipinos, baguios; Chinese, tai-fun; Indians, typhoon. It is the wildest and most destructive of all storms.* Last week Atlantic Coast Americans, who got their word for it from the Carib Indian Huracan (god of stormy weather), were treated to an unusually messy hurricane. For the second time in six years, a tropical cyclone hit the Eastern seaboard with full force (see U.S. AT WAR).

All North American hurricanes start in the same area. Somewhere in “the doldrums,” a generally calm region in the equatorial Atlantic between the Cape Verde Islands and the West Indies, waves of heated air molecules begin to rise from the warm sea. As cooler molecules rush in from the sides to take their place, and the rising air, saturated with ocean vapor, cools off in the upper atmosphere, the air currents move faster & faster. Soon the growing whirlwind, given a counterclockwise spiraling motion by the earth’s rotation (it is clockwise in the Southern hemisphere), resembles a vast phonograph record, with a hollow core, the vortex or “eye” of the storm, through which the sun may shine on the turbulent sea below.

Northwest Passage. Nudged by westerly trade winds, the whirling disk begins to move northwest, picking up speed as it goes. Eventually the howling hurricane builds up to a diameter of 300-600 miles, whirls at 75 to 140 m.p.h. The most violent gusts are at its leading edge. Sucking up water from the sea, which may rise 20 feet, the disk roars on at 10 to 50 m.p.h. along the path of least resistance, i.e., in the direction of lowest pressure. In the path over which a northbound vortex passes, the storm first blows from the east, offers a brief lull at its 8-to-10-mile eye, then hits from the west. Average life of a hurricane is nine days.

Last week three Army flyers deliberately flew into the hurricane to observe it. The A20 Havoc bomber, bucking winds of 125 m.p.h., reached the eye of the storm off Chesapeake Bay, got safely back to Washington. The flyers (Colonel Lloyd B. Woods, ist Lieut. Frank Record, Major Harry Wexler, a meteorologist) reported that it was not as bad as flying through a summer thunderstorm. Their chief scientific observation: besides its horizontal circular motion, a hurricane has strong upward air currents at its vortex and down currents at its perimeter. The plane was sucked up so steeply at the vortex that it was “just like going up in an elevator.”

September is the hurricane season, and each season produces an average of three. Usually, after traveling northwest toward Florida, hurricanes hit a high-pressure coastal front and veer seaward toward a low-pressure area south of Greenland. But last week’s storm, like that in 1938, was funneled inland by the coincidence of a low-pressure front near the Great Lakes. The fiercest hurricane in U.S. history was the 1900 Galveston (Tex.) storm, which killed 6,000. The 1938 storm, still considered the most destructive on record, caused damage estimated at $500,000,000.

* Not to be confused with the tornado, a whirlwind shaped like an inverted cone, which follows a very narrow course, usually spends itself within a few miles.