Damage from windborne debris is a major contributor to the total damage produced by extreme wind of all types. Therefore it is important to incorporate this component into a complete wind-induced damage model, developed for disaster management or insurance purposes. This paper describes the basic methodology for windborne debris damage modelling developed for Geoscience Australia as part of the VAWS model. VAWS is a software tool currently under development that models damage to buildings from severe wind. The implementation of the windborne debris damage model is described in Wehner et al, 2010. Presented at the 14th Australasian Wind Engineering Society Workshop 2010

Monash University under commission of Geoscience Australia produced an offshore wind capacity factor map assessed at a 150m hub height applying the Bureau of Meteorology 10 year (2009-2018) “Bureau of Meteorology Atmospheric high-resolution Regional Reanalysis for Australia” (BARRA) hindcast model. The wind capacity factor has been calculated using the bounding curve of all scaled power curves for wind turbines available within the Open Energy Platform as of 2021. Average wind capacity factor values were also calculated for the Vestas V126 3.45MW and the GE V130 3.2MW wind turbines and are available in this web map service.

Wind multipliers are factors that transform wind speeds over open, flat terrain (regional wind speeds) to local wind speeds that consider the effects of direction, terrain (surface roughness), shielding (buildings and structures) and topography (hills and ridges). During the assessment of local wind hazards (spatial significance in the order 10's of metres), wind multipliers allow for regional wind speeds (order 10 to 100's of kilometres) to be factored to provide local wind speeds. <b>Value: </b>The wind multiplier data is used in modelling the impacts (i.e. physical damage) of wind-related events such as tropical cyclones (an input for Tropical Cyclone Risk assessment), thunderstorms and other windstorms. <b>Scope: </b>Includes terrain, shielding and topographic multipliers for national coverage. Each multiplier further contains 8 directions.

Of the damage sustained by residential buildings during a severe wind event, a significant portion can be caused by impacts from wind‐borne debris. Furthermore, where such impacts form dominant openings in windward walls, large internal pressures can be generated, consequently leading to substantially increased loads on the building’s structure and hence increased damage to the building’s envelope. Geoscience Australia, together with its collaborators the Cyclone Testing Station at James Cook University and JDH Consulting, have commenced development of a software tool to quantitatively model vulnerability of residential buildings to severe wind. This paper describes the implementation of the methodology presented in Part 1 [1] into the software tool to model wind‐borne debris induced damage. Presented at the 14th Australasian Wind Engineering Society Workshop 2010

Geoscience Australia has produced a National Tropical Cyclone Hazard Assessment (TCHA18). The 1%/0.2% Annual Exceedance Probability Maps provides 0.2-second duration, 10-metre above ground level gust wind speeds across Australia arising from tropical cyclone events over a 2-km grid, for 1% and 0.2% annual exceedance probability (100- and 500-year annual recurrence interval respectively). Surface conditions are assumed to correspond to terrain category 2 conditions as defined in AS/NZS 1170.2 (2011).

The northwest Australian coastline from Broome to Exmouth has experienced the greatest number of landfalling Tropical Cyclones (TCs) in Australia since records began in 1908 (Bureau of Meteorology, 2020). Despite this, direct impacts of a TC on individual communities are comparatively unusual, especially for severe TCs (category 3-5) as the coastline is sparsely populated. Communities are generally hundreds of kilometres apart, and a TC can cross the coast between them with little impact. However, the highest recorded wind gust in the world was 408 km/h (category 5) at Barrow Island during TC Olivia on 10 April 1996 (Courtney et al., 2012). The highest wind gust on the Australian mainland was 267 km/h (category 4) at Learmonth during TC Vance on 22 March 1999 (Australian Bureau of Meteorology, 2000). This emphasises the fact that no regional centre in WA, with the exception of Exmouth, has experienced a high-end TC impact in the past 30 years, but there is the potential for extreme events to strike these communities. While the impacts of past cyclone events have been well-documented, it is unlikely that communities have experienced the ‘worst-possible’ (either most intense or most damaging) cyclone impact in the past 30 years. To understand the scale of impacts that would occur if a TC were to make a direct impact on any of these communities the West Australian Department of Fire and Emergency Services (DFES) applied for funding through the Natural Disaster Resilience Program. In July 2017 funding was obtained to conduct the Severe Wind Hazard Assessment (SWHA) project. This initiative is aligned with the National Disaster Risk Reduction Framework (Department of Home Affairs, 2018), which outlines a national, comprehensive approach to proactively reducing disaster risk in Australia. To better understand the potential impacts of cyclones and extra-tropical transitioning cyclones on Western Australian communities, the project has modelled a number of scenarios to demonstrate the impacts of realistic, but perhaps not experienced, cyclones for Broome, Port Hedland, South Hedland and Wedgefield, Karratha, Dampier, Roebourne, Wickham and Point Samson, Exmouth, Carnarvon, Geraldton and Perth A consistent message that comes from this analysis is the excellent performance of modern residential construction to withstand the impacts of these scenario TCs. However, a house built to code’s performance is reliant on being maintained during its life so that its resilience is retained; just because a building was built to standard doesn’t mean it has been maintained to that standard. Investigations conducted into previous cyclones demonstrate that houses built pre-1980s (pre-code) under perform and offer lesser protection compared to those houses built to code post-1980s. In line with that the work undertaken in this report shows clearly that communities with a larger proportion of pre-code residential construction will suffer greater damage, due to the greater vulnerability of older building stock. Houses not originally built to current standards cannot, in general, be expected to perform to the current design levels, irrespective of the maintenance level. The only way to increase performance of these older residential buildings is to retrofit to modern standards. The analysis undertaken in the project has provided emergency managers from local, district and State level with a wealth of information on the potential impacts a major cyclone would have on Western Australia. This information has provided opportunity to strengthen planning processes and raise community awareness of mitigation actions that can reduce impacts. This collection comprises reporting and data developed as part of the Severe Wind Hazard Assessment for Western Australia. The collection includes all reports, publications (e.g. conference presentations, posters and news articles, etc.), and data delivered to Department of Fire and Emergency Services (Western Australia).

The national Tropical Cyclone Hazard Assessment (TCHA) defines the severe wind hazard posed to Australia based on the frequency and intensity of tropical cyclones making landfall around the Australian coastline. Contact us at hazards@ga.gov.au if you need further information. URL: https://www.ga.gov.au/about/projects/safety/tcha <b>Value: </b>The TCHA provides vital information to emergency managers, town planners and infrastructure owners to plan and reduce the threat of tropical cyclone hazard on the Australian coast, and for the insurance industry to understand the tropical cyclone risk as an input to pricing insurance premiums. The TCHA is a key data source to calculate local cyclone impact models for the development of evidence-based disaster management plans, evacuation plans or inform infrastructure planning or mitigation strategies. High risk areas can be identified and prioritised for further analysis, or to extract scenarios to explore risk mitigation and community safety at a local and regional level. The TCHA includes a catalogue of synthetic tropical cyclone events (including tracks and wind fields), hazard profiles for selected locations across Australia, and maps of annual recurrence interval (ARI) wind speeds due to tropical cyclones. Geoscience Australia provides essential evidence based information to government and emergency managers around Australia to improve our communities' ability to prepare for, mitigate against and respond to natural disasters. <b>Scope: </b>Continental scale.

Monash University under commission of Geoscience Australia produced an offshore wind capacity factor map assessed at a 150m hub height applying the Bureau of Meteorology 10 year (2009-2018) “Bureau of Meteorology Atmospheric high-resolution Regional Reanalysis for Australia” (BARRA) hindcast model. The wind capacity factor has been calculated using the bounding curve of all scaled power curves for wind turbines available within the Open Energy Platform as of 2021. Average wind capacity factor values were also calculated for the Vestas V126 3.45MW and the GE V130 3.2MW wind turbines and are available in this web map service.

Windstorms cause most of the damage to housing in Australia. Population growth is exposing more people and buildings to risks from these wind hazards. Houses and components are currently designed and built to standards aligned with the Building Code of Australia. Regulatory measures including building inspections are meant to ensure acceptable quality of construction. Inspections and post windstorm damage surveys have consistently shown that contemporary houses (post 1980) perform better than older houses (pre 1980) in cyclone and non cyclone areas. However, errors in design and construction found during recent surveys, reduce the resilience of contemporary housing. Geoscience Australia is developing a software tool for assessing the vulnerability of housing, using empirical models, expert opinion, and engineering methods. These models could be used to assess vulnerability of a range of house types and also recommend adaptation measure to account for increases in the intensity of windstorms in Australia.

<div>The region of coastal South East Queensland (SEQ) is a large concentration of population, industry, and infrastructure important to the economy of Queensland and of Australia. The region is also subject to severe storms that generate damaging winds, particularly as result of thunderstorm and tropical cyclone activity. Older residential housing has historically been the most damaged in such storms, contributing disproportionately to community risk. This risk posed by severe wind is not well understood, nor are the optimal strategies for managing, and potentially reducing, this risk. In this hazard context, this project was initiated based on a joint proposal developed by Queensland Fire and Emergency Services (QFES), Geoscience Australia and the six coastal local governments in SEQ in January 2020. The objective was to gain an improved understanding of the wind risks in this region and to develop actionable information that could inform future strategies to manage and reduce risk in these areas, with broader application to other local government areas. The project proved to be of great interest to a broader range of stakeholders, including the insurance industry, some of whom became formal partners, while others participated as observers. </div><div><br></div><div>The management of wind risk requires a sound evidence base for decision makers. While the information developed in this project has significant uncertainties, the outcomes are considered a representative view of wind risk in a coastal region that is home to nearly 60% of the Queensland population. The work has developed an improved understanding of the three primary risk elements of wind hazard, residential exposure and vulnerability. This has been achieved through a broad collaboration that has entailed the sharing of data, domain expertise and consensus building. This, in turn, has been translated into an assessment of scenario impacts, local scale risk, and the nuancing effects of resilience on the outcomes. An exploration was carried out of the effectiveness of a range of retrofit strategies directed at addressing the residential buildings in our communities that contribute the most wind risk in South East Queensland. The outcome are expected to be a valuable resource for all the project partners and stakeholders in the areas of planning, preparation, response, recovery and strategic mitigation.</div>