West Experiencing Longer Droughts, More Erratic Rainfall

A study by the USDA’s Agricultural Research Service and the University of Arizona says that dry periods between rainstorms have become longer and annual rainfall has become more erratic across most of the western United States during the past 50 years. According to study authors, rain has been falling in fewer and sometimes larger storms, with longer dry intervals between. Total yearly rainfall has decreased by an average of four inches over the last half century, while the longest dry period in each year increased from 20 to 32 days across the West. The scientists did note that exceptions to these drought patterns were seen in Washington, Oregon, and Idaho and the Northern Plains region of Montana, Wyoming, and the most western parts of North and South Dakota, where total rainfall has increased and drought intervals decreased. “Consistency of rainfall, or the lack of it, is often more important than the total amount of rain when it comes to forage continuing to grow for livestock and wildlife, for dryland farmers to produce crops, and for the mitigation of wildfire risks,” co-senior author Joel Biederman said.