Flash floods in the Caribbean: Environmental conditions and Mitigation

The occurrences of floods and other extreme weather events have devastating effect in the Caribbean. Much attention is given to the destruction caused by a major hurricane but such events are rare for a single territory. Far more frequent are heavy precipitation, severe weather, and drought that cause deaths and serious damage to the economy for which little international assistance is available. Forecasting flash floods presents a great challenge for small Caribbean islands where forecasters are handicapped by the lack of a high-resolution observation network and predictive model to resolve small scale processes. In addition, steep terrain aggravates heavy rainfall by enhancing uplift and creating small-scale zones of convergence.

Usually, official and public awareness of floods is heightened during the summer-fall rainy season. However, flash floods during the dry season (January-March), sometimes catch the population off guard. This study examines flash floods in Jamaica and Puerto Rico and the subsequent mitigation measures that have been implemented. During January through March 1998, for example, winter storms moved well south of their normal tracks enhancing the precipitation potential of fronts in the Caribbean. Areas close to the highest terrain in the islands felt the most adverse effect.

Disaster mitigation is constrained by the weakest link in the detection-forecasting-warning-response process. This study addresses the entire process for these cases and discusses procedures for improvements in professional training, planning, and public education.