Damages scale as a supporting tool for windstorm early warning system in Malaysia

Abstract

It is a fact that windstorm is a natural disaster that can create enormous damages. Thus, the article aims to serve as a guideline in establishing the damages scale as the supporting tool in the windstorm disaster management. The purpose of the scale is to mitigate impacts of windstorm via early warning system, so that local authorities and public at the affected area are able to know the worst-case scenario if windstorm occurred and could make early preparation in minimising the impacts. The damage scale is established based on the current damage criteria as an early warning of windstorm occurrences was adopted from the damages scale which was established outside Malaysia. On the other hand, there is no damages scale originally established in the country. In order to establish this supporting tool, 51 windstorm occurrences in year 2012 to 2016 from 6 districts in Peninsular Malaysia were selected as a study case and 246 damages were assessed. Besides windstorm damages, gust speed, wind direction, rainfall and radar images as raw data, the study also acquires local conditions wind multiplier map coordinated with meteorological station and overlaid with wind direction map at the study area as well. All the damage locations for each windstorm occurrence will be coordinated in the local conditions wind multiplier map. However, the damages which located underneath the same convective cluster with meteorological station, in position with wind direction and gust speed greater than hazard threshold only will be determined its associated intensity. The scale listed each potential damage according to categories either building, property, or tree. The gust speeds at 1-minute in the scale are between 9.0 m/s to 19.3 m/s. From the study, damages scale has similar hierarchy of level damages with existing damages scale but much lower intensity. Damages scale needs to be continuously updated with a new potential damage especially the damages caused by gust speed greater than 19.3 m/s, so that the application of the scale can be extended subjected to more windstorm occurrences and affected areas. This ensures that the scale is applicable to be used in the country throughout the time.