Record temperatures are expected to hit California starting Thursday — right as details emerge about the megadrought ailing the state. As it turns out, the western United States is the driest it’s ever been in at least 1200 years, according to a UCLA analysis.

California’s Sierra snowpack sits at just 38% of its average, which spells trouble for the amount of water the state will have access to this year, says Andrew J. Schwartz. He’s the lead scientist and station manager at University of California, Berkeley’s Central Sierra Snow Lab.