Atmospheric patterns resembling those that appeared during the latter half of California’s ongoing multiyear drought are becoming much more common, a new study finds.

“The current record-breaking drought in California has arisen from both extremely low precipitation and extremely warm temperature,” says Noah Diffenbaugh, associate professor of earth system science at Stanford University.  “In this new study, we find clear evidence that atmospheric patterns that look like what we’ve seen during this extreme drought have in fact become more common in recent decades.”