A Low Yankee Trick
The first attempts to influence hurricanes date back to the 40’s and the origin of cloud seeding, pioneered by Langmuir, Schaefer and Vonnegut. In 1947 under Project Cirrus, Langmuir attempted the method of dispersing dry ice at an altitude of 19,200 feet to force high concentrations of ice nuclei into the previously free upper atmosphere. These regions acted as holding reservoirs until the ice crystals had grown to precipitation size and were then entrained into the lower levels of towering cumuli (lower clouds).
It was perhaps intended originally by Langmuir that over-seeding (creating too many ice nuclei) would reduce the hurricane’s intensity by cutting off the source of moisture.
This worked on cirrus clouds over land, as the greater number of ice nuclei spread the available water vapour too thin to facilitate the formation of ice crystals large enough to rain out. However, the virtually limitless source of water below hurricanes whilst over the oceans would eventually bring even the vast quantities of ice nuclei to precipitation size and reinvigorate the storm after a brief stall.
This is what happened with Langmuir`s hurricane, it stalled for a short period, before growing bigger and darker and making a 90-degree left turn into Georgia, “a low Yankee trick.” as one journalist put it.
A hurricane tends to move first in a westward direction with the trade winds, but as the storm spins, anti-clockwise in the northern hemisphere, it slides away from the equator and is usually deflected in a parabolic curve eastwards.
About 20% of the direction of a hurricane is influenced internally by the effect of its size on what is called Beta Drift. Beta Drift causes the hurricane to head North West. The larger the hurricane the stronger and faster it will head in that direction. This is likely to have been a major influence in the sudden shift in direction to the west.
In any case, Langmuir was pleased, which is disconcerting as he was supposed to be in the business of mitigation. Indeed, it is difficult to see how fuelling a hurricane can reduce its capacity for destruction. Whatever the case, the fellows in the business of litigation were not so pleased. GE’s lawyers told him not to boast about his achievement before the statute of limitations ran out.
We can see the signs here of company and government officials attempting to play down the effects of cloud seeding, not because it doesn’t work but because of the consequences of a public awareness of official involvement with such activities.