Using Lightning Data to Better Understand and Predict Flash Floods in the Mediterranean

Abstract

One of the costliest natural hazards around the globe is flash floods, resulting from localized intense convective precipitation over short periods of time. Since intense convective rainfall (especially over the continents) is well correlated with lightning activity in these storms, a European Union FP6 FLASH project was realized from 2006 to 2010, focusing on using lightning observations to better understand and predict convective storms that result in flash floods. As part of the project, 23 case studies of flash floods in the Mediterranean region were examined. For the analysis of these storms, lightning data were used together with rainfall estimates in order to understand the storms' development and electrification processes. In addition, these case studies were simulated using mesoscale meteorological models to better understand the local and synoptic conditions leading to such intense and damaging storms. As part of this project, tools for short-term predictions (nowcasts) of intense convection across the Mediterranean and Europe, and long-term forecasts (a few days) of the likelihood of intense convection, were developed and employed. The project also focused on educational outreach through a special Web site http://flashproject.org supplying real-time lightning observations, real-time experimental nowcasts, medium-range weather forecasts and educational materials. While flash floods and intense thunderstorms cannot be prevented, long-range regional lightning networks can supply valuable data, in real time, for warning the public, end-users and stakeholders of imminent intense rainfall and possible flash floods.

Selection of intense rainfall events based on intensity thresholds and lightning data in Switzerland

“…Our study complements other recent efforts focused on using lightning observations to better understand and predict convective storms and their consequences, for example, flash floods (Price et al, 2011a, b;Koutroulis et al, 2012).…”

An overview of the lightning and atmospheric electricity observations collected in southern France during the HYdrological cycle in Mediterranean EXperiment (HyMeX), Special Observation Period 1

“…Links between severe weather phenomena including lightning flashes, tornadoes, hail storms, wind gusts and flash floods have been studied for many years. As IC observations were not widely recorded and disseminated, numerous investigations used CG reports to predict severe weather (e.g., Price et al, 2011;Kohn et al, 2011). However, in the past decade it has been shown that the total lightning activity is a more reliable indicator of severe weather (e.g., MacGorman et al, 1989;Goodman et al, 1988;Williams et al, 1999;Montanyà et al, 2007).…”

Simulating lightning into the RAMS model: implementation and preliminary results

“…Starting from those statistics, the probability of detection (POD), false alarm rate (FAR), the bias, and the equitable threat score (ETS) were computed (Price et al, 2011;Lynn et al, 2012;Wilks, 2006):…”

“…The FLASH project (Price et al, 2011) aimed at improving the understanding and forecasting ability of flash floods in the Mediterranean region using lightning data. It was found that real-time lightning observations on a regional basis are very useful in detecting, monitoring and tracking intense thunderstorm activity on large spatial scales.…”