Causas atmosféricas de dos descomunales llenas en la rambla de Nogalte (cuenca del Segura)

Abstract

The Rambla de Nogalte only deviates from its endorheic nature when torrential rain causes severe floods; then, its waters split and some flows along intermediate watercourses to eventually reach the Guadalentín and Almanzora rivers. With a catchment area located in the Baetic massif of the Sierra de las Estancias and covering a total surface area of 139 km2, the Nogalte fundamentally operates as prototypical flood drainage. In less than half a century, a much lower return period than statistically expected, this watercourse has registered two enormous and almost unimaginable floods, on October 19, 1973, and September 28, 2012, with estimated peak flows at Puerto Lumbreras of 1,974 and 2,489 m3/s respectively; the highest ever recorded for this type of watercourse in the Segura Basin. Both events were triggered by torrential rain associated with a sudden drop in temperature accompanied by surface conditions that were exceptionally conducive to creating very heavy local rainfall with a high hourly concentration.