It sounds like science fiction, but humans have the power to change the weather. What they don’t have, though, is enough data about how well it works. That’s according to a new study from the Government Accountability Office, which recently released a report on cloud seeding – a technology that adds chemical compounds to existing clouds and can cause them to drop more rain or snow. Cloud seeding can seem like an obvious solution for the drought-stricken Colorado River Basin, which gets most of its water from Rocky Mountain snowmelt and has seen a downward trend in annual supplies. Historically, policymakers have been slow to embrace the technology, choosing to focus more money and energy on reducing water demand rather than increasing water supply. Meanwhile, advocates for the practice say increased cloud seeding makes sense now.