Meteorology: What Made Betsy Blow

Before the first H-bomb was exploded, there were only a few pounds of tritium—a triple-weight, radioactive form of hydrogen—in the atmosphere and in all the world’s seas. By the end of 1962, when the Russians and the U.S. had ended their atmospheric testing, the tritium released by H-blasts had increased the total to about 600 Ibs. The proliferation of the relatively harmless isotope has been of little concern to most laymen and scientists, but it has enabled University of Miami Chemist Gote Ostlund to draw an important conclusion about hurricanes: instead of getting most of their energy from condensing atmospheric water vapor, as meteorologists previously believed, they are powered largely by vapor sucked up from the sea.

Ostlund’s findings, which he reported last week to a Miami conference on tropical oceanography, were derived from samples of water vapor he collected in September during harrowing “hurricane hunter” plane flights through Betsy, the storm that ravaged the Gulf Coast and New Orleans. Though the amount of tritium in atmospheric water vapor over the central Atlantic and the Caribbean is usually from eight to ten times the quantity in sea water, the concentration in the samples Ostlund collected decreased as the plane approached the storm center. In the vapor in the cloud wall surrounding the storm’s eye, for example, the tritium content was only twice as high as in sea water.

Only one conclusion seemed plausible to Ostlund: the decrease in tritium in his samples resulted from the dilution of atmospheric vapor with relatively tritium-free vapor drawn up from the sea. For every ounce of atmospheric vapor in Hurricane Betsy, he calculated, there were almost two ounces of sea water vapor—a finding that strongly suggested Betsy had derived about 60% of her energy from the sea.

If Ostlund’s preliminary findings are confirmed by further tests, hurricane fighters may have to take a new approach to their job. Instead of seeding clouds to deprive the big storms of energy from atmospheric water vapor, as planned for next year’s Project Storm Fury, they may have to find ways to isolate the hurricanes from their principal source of energy, the sea. One suggestion advanced at the Miami meeting: to cover large areas of the sea in the vicinity of a hurricane with a thin chemical layer—perhaps of fatty alcohols—that would prevent evaporation and keep energy from rising into the storm.