Hailstorms are severe weather events with the potential for devastating impacts. The consequences can be significantly worsened when hail events are accompanied by strong winds, intensifying both hail momentum and damage to property sidings and windows. Additionally, rainfall extremes during hailstorms can disrupt the drainage systems, potentially leading to flash flooding. Therefore, understanding the inter-dependencies and joint behaviour of these hazards is crucial for developing effective risk mitigation strategies. In this study, we conduct a multivariate probabilistic assessment of concurrent hail, wind, and rainfall extremes over the Alberta's “hail alley” using radar and ground-based observations. The analysis comprehensively explores individual hazards, as well as bivariate and trivariate scenarios using a vine copula approach. We quantify individual, conditional, and joint return periods (JRPs) for the various scenarios. Findings indicate that in both wind-driven hail and hail-rainfall extreme hazards, the joint occurrences based on JRP, can be underestimated by 20% and 70% when assuming independence, respectively, which has substantial implications for risk assessment and management, as well as infrastructure design and maintenance. The analysis of the trivariate case suggests the potential for the concurrent occurrence of multiple hazards in the region. Furthermore, results show that Archimedean copula families outperform elliptical copulas in simulating extreme variables related to compound events associated with hailstorms. The study stresses the importance of assessing the joint behaviour of these hazard components in hailstorms, with the objective of mitigating potential impacts on vulnerable regions.

中文翻译：

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阿尔伯塔省冰雹巷中复合冰雹、风和降雨极端值的多变量分析


冰雹是可能造成毁灭性影响的恶劣天气事件。当冰雹事件伴有强风时，后果可能会显着恶化，从而加剧冰雹势头并损坏财产壁板和窗户。此外，冰雹期间的极端降雨会破坏排水系统，可能导致山洪暴发。因此，了解这些灾害的相互依赖关系和共同行为对于制定有效的风险缓解策略至关重要。在这项研究中，我们使用雷达和地面观测对艾伯塔省“冰雹巷”上同时发生的冰雹、风和降雨极端事件进行了多变量概率评估。该分析使用 vine copula 方法全面探讨了单个危害以及双变量和三变量情景。我们量化了各种情景的个人、有条件和联合返回期 （JRP）。研究结果表明，在风驱动的冰雹和冰雹-降雨极端灾害中，基于 JRP 的联合事件在假设独立性时分别可以低估 20% 和 70%，这对风险评估和管理以及基础设施设计和维护具有重大影响。对三变量案例的分析表明，该地区有可能同时发生多种灾害。此外，结果表明，阿基米德 copula 家族在模拟与冰雹相关的复合事件相关的极端变量时优于椭圆 copulas。该研究强调了评估这些灾害成分在冰雹中的联合行为的重要性，目的是减轻对脆弱地区的潜在影响。