Combining new machine learning-based hydroclimate (water balance) reconstructions with new climate simulations, an international team of researchers has now resolved a long-standing issue on identifying the drivers behind millennial-long megadroughts in Northeast America. As confirmed by the new set of reconstructions, the landscape of the vast prairies, extending from the Rocky Mountains to the North Atlantic in Northeast America, was much drier for most of the past 12.000 years.