The 1934 drought was worst of the last millennium

A press release from the American Geophysical Union: The 1934 drought was by far the most intense and far-reaching drought of the last 1,000 years in North America, and was caused in part by an atmospheric phenomenon that may have also led to the current drought in California, according to a new study.

New research finds that the extent of the 1934 drought was approximately seven times larger than droughts of comparable intensity that struck North America between 1000 A.D. and 2005, and nearly 30 percent worse than the next most severe drought that struck the continent in 1580.

“We noticed that 1934 really stuck out as not only the worst drou
ght but far outside the normal range of what we see in the record,” said Benjamin Cook, an environmental scientist at NASA’s Goddard Institute for Space Studies in New York City and lead author of a new paper that has been accepted for publication in Geophysical Research Letters, a journal of the American Geophysical Union.

The new study also finds that the same atmospheric pattern of a high pressure ridge over the West Coast deflecting away storms laden with rain last winter was also present over the area during the winter of 1933-34.

This ridging pattern has preceded some of the worst West Coast droughts, including the 1976 California drought—the beginning of a two-year dry spell which is widely regarded as one of the most severe droughts in the state’s history. The three-year drought currently crippling California will cost the state $2.2 billion in 2014 alone, and will likely continue through 2015, according to a recent report from the University of California, Davis.

Yet the current drought is nothing, so far, compared to what occurred in 1934, the start of a decade-spanning drought that would come to be known as the Dust Bowl and was one of the worst environmental disasters in the history of the United States.

The drought, which afflicted nearly 72 percent of the western United States, was likely made even worse by atmospheric effects from human-created dust storms, according to the new research. The new study suggests that such interactions between the land and the atmosphere may have an important role to play in drought severity, said Cook, who holds a joint appointment at Columbia University’s Lamont-Doherty Earth Observatory....

Arthur Rothstein's 1936 of a dust storm in the Texas Panhandle