The 1934 drought that helped kick off the Dust Bowl era was the worst to hit North America for the past 1,000 years, according to a new study.
Scientists from NASA and Columbia University’s Lamont-Doherty Earth Observatory reconstructed the history of droughts in the U.S. using modern practices and tree-ring records from the years 1000 to 2005.
They found that the 1934 drought covered more than 70% of western North America and was 30% severer than the next worst, which struck in 1580.
“It was the worst by a large margin, falling pretty far outside the normal range of variability that we see in the record,” said Ben Cook, a climate scientist at NASA’s Goddard Institute for Space Studies in New York and the study’s lead author.
Cook says a high-pressure system during the west coast’s winter that kept rains at bay, combined with poor land management practices, led to dust storms in the spring.
The study is due to be published in the Oct. 17 edition of Geophysical Research Letters.