Severe Wind Hazard Assessment for South East Queensland - tropical cyclone impact scenarios

The region of coastal South East Queensland (SEQ) represents a large concentration of population, business activity and infrastructure important to the economy of Queensland and Australia. The region is also subject to severe storms that can generate damaging winds, particularly as a result of thunderstorm and tropical cyclone activity. Older residential homes have historically been the most damaged in such storms, contributing disproportionately to community risk, and recent storm damage in Western Australia has indicated that there are issues with modern SEQ homes also. This risk posed by severe wind is not well understood, nor are the optimal strategies for managing and potentially reducing this risk. Previous work has provided insights into the potential impacts of rare storm events in the SEQ region and the vulnerability of residential homes that contribute to them. The Severe Wind Hazard Assessment for Queensland (SWHAQ) project (Arthur, et al., 2021) provided valuable insights on the potential impacts of rare tropical cyclones making landfall in the region. The SWHA-Q project included two storms impacting the Gold Coast that highlighted that credible cyclone events in South East Queensland generating no more than design level wind gusts can have challenging consequences.Five tropical cyclone scenario events were selected by the project partners and modelled to provide a demonstration of the residential housing damage outcomes that could result from plausible storms that could impact South East Queensland. Four storms generated category 3 winds (gusts over 165 km/h) on landfall and were essentially design level events for ordinary residential structures. The fifth (Scenario 3) generated category 4 winds (gusts over 225 km/h) at landfall but was still quite a credible storm for the region. The events highlighted, as did the previous SWHA-Q work, that rare cyclone events of this kind affect all parts of the study region and produce very significant consequences. One design level event (Scenario 2) was found to inflict moderate or greater damage to 39% of the homes in the region, representing a major need for temporary accommodation. One of the events was used as the evidence-based scenario that underpinned Exercise Averruncus – A SEQ Tropical Cyclone Impact held in Brisbane on 15 June 2022 that explored critical issues around preparation for, response to, and initial recovery from the event. It is noted that the scale of impacts from any scenario is contingent on the characteristics of the TC itself (size, intensity, landfall location) and on the landscape in which buildings are located. However, while each scenario is unique, the suite of scenario impacts provide a useful resource for EM planning by local government, emergency services and other agencies with a role in disaster recovery.

昆士兰州东南部沿海区域（South East Queensland，简称SEQ）是人口、商业活动与基础设施的高度集聚地，对昆士兰州乃至澳大利亚的经济具有重要支撑作用。该区域同时面临强风暴威胁，此类风暴可引发破坏性大风，尤以雷暴与热带气旋活动催生的灾害最为突出。长期以来，老旧住宅是这类风暴中受损最严重的建筑类型，其在社区灾害风险中的占比远超合理水平；近期西澳大利亚州遭遇的风暴灾害亦表明，SEQ地区的现代住宅同样存在相关风险隐患。

强风带来的此类风险尚未得到充分认知，对应的风险管控与缓解最优策略也尚不明确。过往研究已针对SEQ区域罕见风暴事件的潜在影响，以及由此引发的住宅建筑脆弱性提供了若干洞见。昆士兰州强风灾害评估（Severe Wind Hazard Assessment for Queensland，简称SWHAQ）项目（Arthur等，2021）便为该区域登陆的罕见热带气旋潜在影响提供了宝贵研究成果。该项目纳入了两起影响黄金海岸的风暴案例，研究结果显示，在SEQ区域发生的、风速未超出设计阵风阈值的可信气旋事件，仍可能带来极具挑战性的后果。

项目合作方选取了五起热带气旋情景事件并开展建模，以演示可能袭击SEQ区域的合理风暴情景下，住宅建筑的受损情况。其中四起风暴登陆时达到3级风速（阵风超过165公里/小时），本质上属于普通民用建筑的设计基准事件；第五起（情景3）登陆时达到4级风速（阵风超过225公里/小时），但仍是该区域可信的风暴情景。正如此前SWHAQ项目的研究结论所示，这类罕见气旋事件会波及研究区域的所有区域，并造成极为严重的后果。

经测算，一起设计基准事件（情景2）可导致区域内39%的住宅遭受中度及以上损毁，这意味着需要大规模临时安置用房。其中一起情景事件被用作循证情景，支撑了2022年6月15日在布里斯班举办的"Exercise Averruncus——昆士兰州东南部热带气旋影响演练"，该演练探讨了风暴应对、应急响应与初期恢复等核心议题。

需说明的是，任何情景下的灾害影响规模，均取决于热带气旋本身的特征（规模、强度、登陆地点）以及建筑所处的地理环境。不过，尽管各情景均具有独特性，但这套情景灾害数据集可为地方政府、应急服务机构及其他参与灾后恢复工作的机构提供宝贵的应急管理规划参考资源。