Although the fluffy white clouds in the sky above the Wari archaeological site of Cerro Baúl (500-1,000 A.D) may seem harmless, in southern Peru they are harbingers of drastic environmental changes. El Niño is a climatic event that occurs in the Pacific Ocean and radically alters the local environment, bringing catastrophic flash floods to the normally arid coast of Peru as well as drought and bitter cold to the highlands. This photo, taken in the summertime when blue skies are the norm, captures an unusual amount of clouds that foretell a coming El Niño. Such environmental disasters would have devastated the ancient inhabitants of the region and my archaeological research in the area of Cerro Baúl has been focused on determining what, if any, impact El Niño made have had on this past society and whether a deteriorating climate affected its collapse.