The flood event that affected Badajoz in November 1997

Abstract

Abstract. The flooding episode of November 1997 in Badajoz was one of the most dramatic catastrophes in Spain: as a result, there were 21 fatalities and huge financial damages. The main purpose of this work is to assess the prevailing synoptic conditions as well as detailing the mesoscale effects by means of moisture sources and dynamic and thermodynamic instability analysis involved in the November 1997 Spanish severe weather episode. In order to achieve the above, this flood event is described in terms of moisture content evolution by means of individual particle simulation along 3-day back-trajectories. A Lagrangian model is applied in order to characterize the atmospheric particles involved in the focused case (localization, height and specific humidity) which give rise to sudden precipitation stream. Geopotential height and temperature fields were used to describe the synoptic situation. Thermodynamic indices, such as CAPE, SWEAT and KI, and dynamic parameters like potential vorticity anomaly at 330 K isentropic surface and Q vector divergence were also calculated in order to complete the analysis and to give a thorough weather frame taking into account the atmospheric instability. The results of this work suggest this flood event was due mainly to strong dynamic instability along with large amounts of moisture advected by a trough, while the thermodynamic instability played a secondary role. Finally, a new methodology based on a technique proposed by Tremblay (2005) has been developed in order to separate the precipitation into stratiform and convective components. It is evident that the event was associated with a predominant convective regime.

A ranking of high‐resolution daily precipitation extreme events for the Iberian Peninsula

“…However, it was more intense ( M = 4.5) than the top rank event and produced major socioeconomic impacts with 11 deaths in Portugal and 21 in Spain (Ramos and Reis, ). According to Lorente et al (), this event was due to a cut‐off‐low that deepened quickly and extended to lower levels just before leaving the Atlantic Ocean. This configuration implied a substantial increase of the large atmospheric instability and consequently triggered strong convection that played a fundamental role in the development of several Mesoscale Convective Systems.…”

Cut‐off low systems over Iraq: Contribution to annual precipitation and synoptic analysis of extreme events

“…We compare the calculated values with the Lorente et al . () thresholds, which were developed for another Mediterranean region (Table S1).…”

“…The Lorente et al . () threshold values for convective instability are included (these are lower‐limit values except for the LI and SI indices).…”

Ranking of multi‐day extreme precipitation events over the Iberian Peninsula

“…Nevertheless, this increasingly arid environment is prone to extreme precipitation days at the daily and longer temporal scales that are often associated with adverse socioeconomic impacts (e.g. Lorente et al , ; Fragoso et al , ; Liberato et al , ; Liberato, ; Trigo et al , ). Until recently, the study of precipitation extremes affecting the entire IP or specific sub‐sectors has been hampered by the unavailability of a sufficiently long and high‐resolution dataset for the whole IP.…”

“…Nevertheless, this increasingly arid environment is prone to extreme precipitation days at the daily and longer temporal scales that are often associated with adverse socioeconomic impacts (e.g. Lorente et al, 2008;Fragoso et al, 2010;Liberato et al, 2012;Liberato, 2014;Trigo et al, 2015). Until recently, the study of precipitation * Correspondence to: A. M. Ramos, Instituto Dom Luiz, Faculdade de Ciências, Universidade de Lisboa, Campo Grande, Edf.…”