Severe Wind Hazard Assessment for Queensland - Tropical Cyclone Scenarios

The Severe Wind Hazard Assessment for Queensland arose as a project to better understand the potential impacts of tropical cyclones (TCs) on population centres and elements of critical infrastructure in Queensland. The rationale for the project was reinforced by lessons from Severe Tropical Cyclone (STC) Debbie, the direct and indirect impacts of which affected a significant area of Queensland, stretching from Bowen to the City of Gold Coast and Northern New South Wales between 28 March and 7 April 2017, resulting in 14 mostly flood associated deaths, and more than A$3.5 billion in direct losses. The intent of the project is to explore and assess a range of scenarios that extend beyond the contemporary recollection of severe events in order to challenge decision making for rarer but higher-consequence events. The scenarios described in the report can be used to improve planning for severe tropical cyclone (TC) events and their impacts. This includes developing a better understanding of how the capabilities of emergency services and supporting elements may be impacted in actual events. Scenarios were selected from the catalogue of synthetic events (i.e. events that did not actually occur but whose occurrence was as probable as those that did occur) generated for the 2018 Tropical Cyclone Hazard Assessment (TCHA; Arthur, 2018), in consultation with Queensland Fire and Emergency Services (QFES) and those local governments involved within the project. Two TC events were modelled for each location for this project – a Category 3 and a Category 5 TC -with ‘favourable’ tracks for impact analysis. In all scenarios, consideration was given to regional historical analogues for the selected synthetic tracks to better relate the scenario outputs to known or “lived” events. These categories were chosen as they represent events with a moderate and very low likelihood with respect to intensity, based on historical observations. This also accounts for the future climate of less TCs but more intense occurrences, highlighting the different impacts arising from different events. It is important to emphasise and understand that each individual TC event will be different and lead to different impacts.

昆士兰州强风灾害评估项目旨在系统探究热带气旋（Tropical Cyclones，TCs）对昆士兰州人口聚居区及关键基础设施各组成部分的潜在影响。本项目的立项依据因强热带气旋（Severe Tropical Cyclone，STC）黛比的灾害教训得到进一步夯实：2017年3月28日至4月7日期间，该气旋的直接与间接影响波及昆士兰州从鲍恩至黄金海岸市及新南威尔士州北部的广袤区域，造成14人死亡（其中多数与洪涝灾害相关），直接经济损失超35亿澳元。本项目旨在探索并评估一系列超出当前公众对强灾害事件认知范畴的情景，以助力优化针对罕见但高影响灾害事件的决策制定。本报告所载各类情景可用于完善强热带气旋（以下简称TC）灾害及其影响的应对规划，其中包括深化对实际灾害发生时应急救援力量及配套支撑体系可能受影响程度的认知。本次项目选取的情景源自2018年热带气旋灾害评估（Tropical Cyclone Hazard Assessment，TCHA；Arthur，2018）所生成的合成事件库——即未真实发生但发生概率与真实事件相当的假想事件——选取过程已与昆士兰州消防与应急服务局（Queensland Fire and Emergency Services，QFES）及项目涉及的各地方政府完成磋商。本项目为每个评估点位分别建模了两类热带气旋情景：3级与5级热带气旋，均选取利于开展影响分析的移动路径。所有情景均参考了区域内与选定合成路径相似的历史灾害案例，以便将情景模拟结果与已知或实际发生过的灾害事件建立更合理的关联。选取这两类等级的情景，是基于历史观测数据，它们分别对应强度发生概率中等与极低的热带气旋事件。同时这一选取也契合未来气候背景下热带气旋总数减少但极端强度事件增多的趋势，凸显不同强度气旋所引发的灾害影响差异。需特别强调并明确的是：每一次热带气旋事件均具备独特性，其所引发的灾害影响也各不相同。