Wind & Water

Hurricane Carla, which smashed into Texas last week, was a whirling doughnut of wind, but like most hurricanes it used water to do its worst damage. Torrential rain raced ahead of the storm, giving Gulf Coast lowlands a preliminary flooding. Then, while the eye of the hurricane was still well offshore, great, white-topped waves cruised out of the sea and crashed across the land. Coastal settlements were washed out; those lying farther inland were flooded by fast-flowing water and picked to pieces by the screaming wind. Buildings that might have been strong enough to stand up to Carla's blasts blew down after wind-driven water undermined their foundations. Trees, water tanks, small boats, and assorted other projectiles swirled inland on Carla's floods and bludgeoned their way across country on her rising tides.

Scientists could only observe and record the pattern of devastation, and pile up data against the day when they may learn how to trick a hurricane into sub mission. One thing the weathermen could claim credit for now: their accurate, timely alarm. Carla did enormous property damage, perhaps a billion dollars' worth, but took few lives. The well-warned people of coastal Louisiana and Texas had fled to safety in the greatest mass exodus in U.S. history. Only a comparative few were killed. There was no mass tragedy as when Hurricane Audrey flooded Cameron, La., in 1957 and killed 590 people.

Mysterious Floods. A hurricane's worst water damage, says Weather Bureau Hurricane Expert Robert H. Simpson, usually occurs in the storm's right forward quadrant. The wind is strongest there because the speed of the hurricane's forward motion is added to the speed of its counterclockwise rotation. And it is there that the highest bulge of water builds up ahead of the storm. Meteorologists can account for only part of the rise. The storm's drop in barometric pressure causes the sea level to rise somewhat as the eye of the hurricane approaches. The pressure difference between Hurricane Carla's out skirts and her central eye was enough to make the sea rise 3 ft. But there are also unexplained causes of flooding, and in other hurricanes unexpected walls of water have converged on a doomed city in minutes. This happened at Galveston in 1900 and Corpus Christi in 1919. No one yet knows why.

The tornadoes that are spawned by powerful hurricanes, and sometimes account for a good part of their damage, are mysterious, too. Meteorologists say that they are caused by the rapidly rising air on the rim of the storm and are similar to the eddies in water flowing out of a bathtub, but no one knows just when to expect the dangerous twisters. Usually they are much smaller than Kansas-type tornadoes, and last only a few minutes, whipping down to earth to splinter a few blocks of buildings and then dissipate.

Experiment at Sea. Although meteorologists do not fully understand hurricanes, they are already toying with schemes for breaking one up. Since a full-fledged hurricane generates the energy of many H-bombs every second, the project sounds like a presumptuous David-and-Goliath act, but the Weather Bureau is in deadly earnest. When the next suitable hurricane appears, the bureau plans to fly seven airplanes through and over the storm. One of the planes, a U2, will operate at 70,000 ft. After the anatomy of the storm has been observed and studied, one of the airplanes will drop silver iodide smoke bombs into a carefully selected spot on one side of the storm. There is some possibility that the silver iodide particles will cause enough condensation to create a small new hurricane, which will steal energy from the main' storm and make it dissipate.

The storm on which this stunt is tried will have to be well out in the Atlantic, preferably heading for Europe. In 1947, the Army, Navy and General Electric Co. meteorologists dumped 120 Ibs. of cloud-forming dry ice into a hurricane off the Georgia coast. The storm broke into two pieces, one of which hit and badly damaged Savannah. Meteorologist Simpson feels sure that before the dry ice was dropped the storm had already begun to break up and turn inland. But, he admits, "you'll never convince Savannah."

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