Heavy Rainfall Effects in Mexico During Early October 1999

Abstract

In the first week of October 1999, heavy rain events occurred in the Eastern slope of the Eastern Sierra Madre of Mexico, with important consequences in at least four states of this country. The effects of the rainfall were a few thousand mass movements, erosion and loss of topsoil, flash floods, and extensive flooding. Damage in three out of the four states accounted for 384 deaths, 66 missing, 212 municipalities with damages, 39 rivers that burst their banks, around 198,000 people were affected, and 48,000 houses affected to a varying degree. In addition, there was a lot of damage to roads and bridges, and serious wreckage to agriculture (data provided by the governments of Puebla, Veracruz, and Hidalgo). Economic losses were massive. In the state of Puebla alone, it is estimated that over 200 million dollars (U.S. $) will be needed for restoring damaged infrastructure (government report, Jan. 15, 2000).

This document shows the most relevant aspects of this disaster that took place in the first week of October 1999. It begins by exposing the general features of the area, such as physiography and rainfall patterns, and describes the meteorological phenomenon that caused such widespread damage, by analyzing the rainfall registered during the critical days. The paper continues by stressing the geological characteristics and other causes that contributed to the mass movements in the Sierra Norte of Puebla state. Finally, damages in different states are described, and a few conclusions and recommendations are put forward.