A methodology to conduct wind damage field surveys for high-impact weather events of convective origin

Oriol Rodríguez,Delia Gutiérrez,Joan Bech,Salvador Castán,Juan De Dios Soriano

doi:10.5194/nhess-20-1513-2020

Abstract

Abstract. Post-event damage assessments are of paramount importance to document the effects of high-impact weather-related events such as floods or strong wind events. Moreover, evaluating the damage and characterizing its extent and intensity can be essential for further analysis such as completing a diagnostic meteorological case study. This paper presents a methodology to perform field surveys of damage caused by strong winds of convective origin (i.e. tornado, downburst and straight-line winds). It is based on previous studies and also on 136 field studies performed by the authors in Spain between 2004 and 2018. The methodology includes the collection of pictures and records of damage to human-made structures and on vegetation during the in situ visit to the affected area, as well as of available automatic weather station data, witness reports and images of the phenomenon, such as funnel cloud pictures, taken by casual observers. To synthesize the gathered data, three final deliverables are proposed: (i) a standardized text report of the analysed event, (ii) a table consisting of detailed geolocated information about each damage point and other relevant data and (iii) a map or a KML (Keyhole Markup Language) file containing the previous information ready for graphical display and further analysis. This methodology has been applied by the authors in the past, sometimes only a few hours after the event occurrence and, on many occasions, when the type of convective phenomenon was uncertain. In those uncertain cases, the information resulting from this methodology contributed effectively to discern the phenomenon type thanks to the damage pattern analysis, particularly if no witness reports were available. The application of methodologies such as the one presented here is necessary in order to build homogeneous and robust databases of severe weather cases and high-impact weather events.

Highlights

Meteorological phenomena associated with strong surface wind of convective origin can cause important disruption to socioeconomic activity, including injuries or even fatalities, despite their local character compared to larger-scale midlatitude synoptic windstorms or tropical storms
The objective of this paper is to propose a methodology to conduct in situ damage surveys of strong wind events from convective origin
Holzer et al (2018) provided useful indications for current field studies, such as visiting affected areas as soon as possible and providing an estimation of the wind intensity for each damaged element given by the pair damage indicator–degree of damage (DI– degrees of damage (DoD)) from the EF scale (WSEC, 2006), to other authors such as Burgess et al (2014)

Summary

Introduction

Meteorological phenomena associated with strong surface wind of convective origin (i.e. tornadoes, downbursts, straight-line winds) can cause important disruption to socioeconomic activity, including injuries or even fatalities, despite their local character compared to larger-scale midlatitude synoptic windstorms or tropical storms. In situ damage surveys are especially useful to determine which phenomenon took place when there is an absence of observations by analysing damage patterns on forest and how debris is spread (Hall and Brewer, 1959; Holland et al, 2006; Bech et al, 2009; Beck and Dotzek, 2010; Rhee and Lombardo, 2018) This information can be added to natural hazard databases such as the US Storm Prediction Center Severe Weather Database (Verbout et al, 2006) or the European Severe Weather Database (Dotzek et al, 2009), making it possible to build up robust and homogeneous datasets, improving the knowledge of spatial–temporal distribution and characteristics of tornadoes, downbursts and straight-line winds. Holzer et al (2018) provided useful indications for current field studies, such as visiting affected areas as soon as possible and providing an estimation of the wind intensity for each damaged element given by the pair damage indicator–degree of damage (DI– DoD) from the EF scale (WSEC, 2006), to other authors such as Burgess et al (2014)

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Discussion

Conclusion