Western states that were thought to be resistant to prolonged drought may be more vulnerable than scientists previously believed, a new analysis of groundwater reserves in the Colorado River Basin finds.Researchers revealed the four states that together make up the Upper Basin — Colorado, New Mexico, Utah and Wyoming — lost almost twice as much groundwater as the Lower Basin did during an intense drought in the southwestern U.S. between 2020 and 2022. The finding was unexpected and might signal a turning point for the region, because the Upper Basin has long been seen as more resilient to dry spells than the Lower Basin, said Esther Oyedele, a doctoral student in geosciences at Virginia Tech...