Drought of 1934 was the Worst in Past 1,000 Years

Drought of 1934 was the Worst in Past 1,000 Years

October 17, 2014; 4:49 PM ET

Scientists from NASA have determined that the drought of 1934 was the driest and most widespread drought in North America over the past 1,000 years.

The research team utilized tree ring data from the years 1000 to 2005 and more modern records to conduct their study.

What they found was that the 1934 drought, which covered 71.6 percent of western North America at it's peak was 30 percent more severe than the drought of 1580, which was the second worst drought during the period of record.

Palmer Index map from July 1934

Two key factors were responsible for the severity and extent of the drought, according to the report. A persistent, blocking high pressure system that anchored along the West coast, forcing storms away from the region and poor land management practices, which enhanced dust storms.

Key excerpts from the report.....

"It was the worst by a large margin, falling pretty far outside the normal range of variability that we see in the record," said climate scientist Ben Cook at NASA's Goddard Institute for Space Studies in New York. Cook is lead author of the study, which will publish in the Oct. 17 edition of Geophysical Research Letters.

"In combination then, these two different phenomena managed to bring almost the entire nation into a drought at that time," said co-author Richard Seager, professor at the Lamont-Doherty Earth Observatory of Columbia University in New York. "The fact that it was the worst of the millennium was probably in part because of the human role."

"We found that a lot of the drying that occurred in the spring time occurred downwind from where the dust storms originated," Cook said, "suggesting that it's actually the dust in the atmosphere that's driving at least some of the drying in the spring and really allowing this drought event to spread upwards into the central plains."

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