Intense Precipitation and Area of Risk: A Case Study of Mass Movement in the City of Natal, Brazil

Abstract

This study aims to analyze the atmospheric conditions associated with an event of intense precipitation caused by Easterly Wave Disturbances (EWDs), as well as the environmental conditions related to the mass gravitational movement that occurred between 14th June and 15th June of 2014, in the district of Mãe Luiza, Natal/RN/Brazil. The synoptic conditions, the vertical integrated moisture flux and the energetic behavior in the EWD’s performance phases were analyzed. In addition to these factors, local environmental aspects were assessed, classifying the vulnerability to disaster events in the affected area. Over the days of the operation of the atmospheric system, the daily accumulation of precipitation was greater than 100 mm, with precipitation accumulated in 3 h in the order of 60 mm for the stages of maturation of the disturbance. The main synoptic conditions associated with EWDs were exhibited by the intense anomalies of wind speed and high humidity flux on the east coast of the Northeast, which intensified the influx of moisture into the continent over the period of the operation of the system. Conditions of high to very high vulnerability were identified in the area where the event took place and also in other expressive parts of the district.