A reconstruction of landfalling tropical cyclones on the Pacific coast of Mexico from 1850 to 1949

The eastern Pacific basin is a very prolific region spawning the largest number of tropical cyclones per unit area in the world. The vast majority of the cyclones have westward tracks, but a small fraction of them move over land, affecting several of the coastal states in Mexico. Analysis of the National Hurricane Center database (1949-2010) indicates a clear intraseasonal variability on the landfall location that is related to large-scale patterns in the atmosphere. However, the relatively short length of the record prevents the study of variability at longer timescales.

In this study we have carried out a systematic search in local newspaper reports and historical documents of events that can be characterized as tropical cyclones affecting the Mexican Pacific states of Guerrero, Jalisco, Michoacán, Sinaloa and Baja California Sur. We have analyzed reports from 1949 back to 1850. A large number of records was found, allowing us to construct a map of the landfalling cyclones over the years and to compare it with the official present record. The spatial and temporal patterns of landfall are similar to the ones observed in the present record. However, there seems to be an opposite behavior between landfalls in the Baja peninsula and Sinaloa on the mainland, at decadal scale, perhaps related to differences in the location of the Pacific high pressure system and the westerly flow that steers cyclones onto Sinaloa later in the season. The results of the total number of landfalling cyclones suggest that there is a multi-decadal variability that modulates the total number of landfalling cyclones, linked to the Pacific Decadal Oscillation. Insignificant correlation is found with the multivariate ENSO index and the Atlantic Multidecadal Oscillation index.