# Vulnerability of Buildings to Meteorological Hazards:
## 1 Introduction  
Meteorological hazards including strong winds, heavy rainfall, and hail can cause casualties and damage to crops, infrastructure, and buildings. Although the impact on buildings caused by meteorological hazards in Europe is not so intense in comparison to other parts of the world (e.g., hurricanes in the Caribbean and the USA), recent events (e.g., hailstorm in Austria 2021, windstorm in Corsica 2022) have clearly shown that this impact is not insignificant. While it is not clear if and how much climate change will affect the magnitude and frequency of these hazards in the future, to reduce the associated risk scientists and practitioners need to understand and analyze the physical vulnerability of the built environment [1]. It is important to emphasize that the present paper focuses on the vulnerability of the elements at risk (in this case buildings) and not the hazard itself, the probability of occurrence, or future projections of its magnitude, frequency, and extension due to climate change. The focus is on the physical impact of three meteorological hazards (windstorms, heavy rain, and hail) on buildings. As far asvulnerability assessment is concerned, recent reviews have emphasized that there is no universal method for analyzing, assessing, or quantifying physical vulnerability to the built environment [2]. Approaches include the development of matrices combining the intensity of a process to expected damages, vulnerability curves assessing the monetary degree of loss under different intensities, and vulnerability indicators expressing the characteristics of buildings that make them vulnerable to the impact of a natural hazard [2]. As far as meteorological hazards are concerned, some efforts for the vulnerability of various elements at risk can be found in the literature. Regarding hail, studies focusing on the vulnerability of crops [3] or solar panels [4] are relatively common. Nevertheless, a limited number of studies focusing on buildings [5] is also present. Vulnerability assessments of buildings subject to strong winds are more common for countries that experience hurricanes [6; 7] and sometimes in combination with vulnerability to storm surges [8]. However, concerning heavy rainfall, most studies focus on the vulnerability to rainfall-induced hazards such as floods, landslides, and debris flows [9].  
In the present paper, we adapt a well-established vulnerability assessment method [10] for meteorological hazards which had originally been developed for tsunamis and was later applied to other hazards. The selection of indicators (characteristics of the buildings) based on the impact that these three hazards have on the building shell is described in the following paragraphs. The weighting of the indicators and their aggregation in an index is then demonstrated. Following the development of three physical vulnerability indices (PVI) for buildings (one for each hazards type), the web application (www.vulni.at, accessed on 7 March 2023) based on the described methodology is presented, which may be used by different users for risk communication and awareness-raising of affected homeowners and planning of local adaptation measures [11]. The novelty of the study lies in the fact that indicator-based approaches for the assessment of physical vulnerability to meteorological hazards are rare. The study takes a closer look at building characteristics that affect their vulnerability to meteorological hazards such as windstorms, hail, and heavy rain and engages experts in order to define their relative importance.