History: Interestingly, this drought occurred during the approximate period when San Lorenzo was abandoned, around 900 B.C. While no evidence links that abandonment to drought, it would be consonant with minor regional collapses in later history, as David Webster, professor of anthropology at Pennsylvania State University, describes the drought cycle data for the later Maya. There is no reason to suppose that the Olmec, with their similar agriculture, would have not been similarly impacted:
Sometimes plenty of rain falls, but it arrives a bit late, or there is an unusually dry interval as the crops ripen. In these circumstances, the harvest might be sparse, but people can generally tighten their belts and get by. More serious are marked deficiencies in annual rainfall extending over one or several years. Such protracted droughts can cause widespread famine, along with disease and social disruption. Many episodes of hunger, death, and conflict related to droughts of this kind are featured in the various Books of Chilam Balam, and scores of historical droughts are also recorded for northern Yucatan during Colonial and later times. Although exact census figures are unavailable, during the worst of them as many as 30–50 percent of the rural Maya population might have died.
This particular drought on the Jaredites may well have resulted in a similar 30–50 percent mortality rate. Moroni’s description underscores the resulting desperation as the deaths spiraled.