Is America facing another Dust Bowl?

Oceanic conditions similar to those that triggered the ruinous "Dust Bowl" drought during the Great Depression of the 1930s appear to be in place, warn meteorologists at AccuWeather.com, State College, Pa. The exceptionally warm waters of the Atlantic Ocean that played a major role in the record-breaking 2005 hurricane season, coupled with cooler-than-normal Pacific Ocean waters, are weakening and changing the course of a low-level jet stream that normally channels moisture into the Great Plains.

The low-level jet stream--a fast moving current of winds close to the Earth's surface--travels from east to west across the Atlantic, then typically curves northward as it crosses the Gulf of Mexico, bringing much-needed moisture to the croplands of the Great Plains. Abnormal sea-surface temperatures have caused this stream to continue westward and to weaken, which is preventing moisture from reaching the agriculturally critical region. The shift also is allowing a southerly flow from Mexico to bring much drier air northward into the Plains.

Besides dramatically reducing precipitation for the region, the changes brought about by the abnormal sea-surface temperatures also should result in higher surface temperatures. "When surfaces are wet, energy from solar radiation simultaneously evaporates moisture and heats the ground," notes chief meteorologist Elliot Abrams. "When no moisture is present, all that energy is channeled toward heating the ground, and the warmer ground heats the lower atmosphere. The combination of low moisture and higher temperatures would be a crippling one-two punch for the Great Plains should these damaging conditions persist, much like what occurred during the Dust Bowl drought."

"It's amazing how dry the Southern Plains are," says Ken Reeves, director of forecast operations. "The recent breakout of lethal wildfires, which killed more people than the tornadoes that were striking at the same time in the Midwest, are just one indication. We're seeing readings of one percent humidity in some areas, which is extreme. Blowing clouds of dust are reducing visibility in places such as Lubbock and Amarillo, Tex., to about a mile or so. To one extent or another, Texas, New Mexico, southeast Colorado, Oklahoma, and southwestern Kansas are all experiencing severe weather that is attributable to a remarkable lack of moisture."

The Dust Bowl was a severe eight-year drought that struck a wide swath of the Great Plains. It was a catastrophic blow to an economy that already was staggering under the weight of the Great Depression. The Dust Bowl undoubtedly was the worst drought in U.S. history, eventually covering more than 75% of the country. Solar radiation heating the parched and blighted land caused temperatures in the region to rise to record-breaking levels.

"The year 1936 was the hottest summer ever recorded across much of the Midwest and East," says Abrams. "Many of the single-day and monthly record-high temperatures across the eastern two-thirds of the country are from that year."

The Dust Bowl also was noted for the huge dust storms that billowed across the Great Plains and swallowed millions of acres of farmland at a time. While a drought of that intensity could occur again, it is highly unlikely that the nation will see a return of the dust storms.

"The dust storms fed off the over-plowed and overgrazed lands of the Great Plains," explains senior meteorologist Dale Mohler. "The agricultural practices at the time, combined with a long period of drought, caused severe damage to farmland in the region. Eventually, the topsoil dried up to the point where it was swept away as great clouds of choking dust that stretched for miles."

Moreover, "It is not a mere coincidence that the Dust Bowl years of the 1930s were marked by years of tremendous hurricane activity," according to chief forecaster Joe Bastardi. "For example, the record-shattering 2005 hurricane season was the first to eclipse 1933 in number of tropical cyclones, and that may only have been because we didn't have satellites in the 1930s to identify the major storms that failed to reach the U.S. coast."

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