 Atmospheric rivers, ARs, are narrow regions of intense precipitation and strong low-level winds that transport moisture from the tropics towards the poles. They play a key role in the global water cycle, but can also lead to devastating flooding if they encounter mountainous terrain. Recent research has focused on understanding the physical processes behind AR formation, their predictability, and how they may change in the future. This article was authored by Luis Ijimeno, Raquel Inieto, Marta Ivasquez, and others.