Development of a windstorm hazard index using structured decision-making and dimensionality reduction techniques based on meteorological, built environment and social parameters

The intensity of windstorms in Peninsular Malaysia growing in both frequency and severity and they are now becoming a significant threat to the public, infrastructure and the economy. Growing dangers aside, it is unfortunate that there is no comprehensive region-specific index that evaluates and categorizes the windstorm threat which results in ineffective planning and disaster mitigation. This study aims to develop a Windstorm Hazard Index (WHI) for Peninsular Malaysia to assess and categorize windstorm risks across the region. Four key objectives were pursued: (1) to identify the significant that influence windstorm events in Peninsular Malaysia. (2) quantifying the effects of these parameters using windstorm data from 2008–2018, numerical simulations (WRF-ARW), and urban morphology analysis via Envi-MET software, (3) formulating the WHI using Analytic Hierarchy Process (AHP) and Principal Component Analysis (PCA), and (4) validating the WHI with real windstorm cases from 2020–2024. The WHI classifies Peninsular Malaysia’s regions into six risk levels: very low (0.1–0.5), low (0.501–0.6), moderate (0.601–0.7), high (0.701–0.8), very high (0.801–0.9), and extreme (0.901–1.0). Southern and central states such as Negeri Sembilan and Pahang exhibited very low risks, while moderate risks were noted in Kelantan and Terengganu. High-risk areas were concentrated in coastal and northern regions, including Penang, Kedah, and Perlis, where climatic and geographical factors intensified windstorm activity. Extreme-risk zones were identified in parts of Perlis and Kedah, necessitating robust disaster preparedness and mitigation strategies. The study revealed that environmental variables such as wind speed, temperature, humidity, and precipitation significantly influenced windstorm hazards. Coastal and high-altitude areas were particularly vulnerable due to stronger wind speeds and atmospheric instability. Land use and urban density further exacerbated windstorm impacts, especially in urban areas like Penang and Johor. Validation of the WHI confirmed its reliability, with extreme-risk events, such as those in Perlis and Kedah, correlating with high wind speeds, significant property damage, and disruptions. The WHI’s practical application was demonstrated through accurate classification of past windstorm events across various states, reflecting both physical and environmental factors affecting storm intensity. In conclusion, the WHI provides a comprehensive framework for assessing windstorm risks and offers valuable insights for urban planning and disaster management. It emphasizes the importance of integrating environmental monitoring and resilient infrastructure into mitigation efforts. This study contributes to hazard preparedness by presenting a sensitivity map that highlights vulnerable regions, guiding policymakers toward effective interventions. Future refinement of the WHI is recommended to adapt to evolving environmental conditions and enhance disaster resilience across Peninsular Malaysia.