Consider you are responsible for providing an emergency response in Karratha. There is a category 4 cyclone sweeping towards the coast and Bureau of Meteorology forecasts indicate the cyclone will intensify to category 5 before landfall. The last time a category 5 cyclone came close to Karratha was in 1999, when Cyclone John passed 80 km east of Karratha, sparing it the worst winds. If it had not turned to the southeast prior to landfall, damage to Karratha would have been much worse. Karratha has also grown substantially since then, with close to half the residential buildings constructed after 1997. As a first responder, are you prepared for the consequences of a direct strike? Do you even know what the extent of the impacts might be? What will Karratha look like immediately after the cyclone passes? If emergency preparation decisions were based on past experience, they would likely fall well short of the required action to minimise impacts. The Severe Wind Hazard Assessment project, funded through the WA Natural Disaster Resilience Program, endeavours to provide emergency managers with realistic, modelled scenarios of cyclone impact in WA communities to inform local, regional and state planning for cyclone risk. By analysing hypothetical scenarios, the Department of Fire and Emergency Services can identify and address gaps in the understanding of the impacts of a cyclone, and improve decision-making processes at coordination and control levels. A first step in this process is to develop hypothetical severe tropical cyclone footprints for WA communities. We use a stochastic tropical cyclone model to generate a catalogue of cyclone events, then select TC tracks meeting the criteria for the exercise: events with specific intensities passing directly over communities. Here we present the hazard footprints of these hypothetical storms, and a preliminary analysis of the impacts on residential buildings. Poster presented at the 2018 Amos-ICSHMO Conference Sydney, NSW (https://www.ametsoc.org/index.cfm/ams/meetings-events/ams-meetings/amos-icshmo-2018/)

Tropical Cyclone (TC) Debbie made landfall near Airlie Beach, Queensland on the 28th March 2017 as a category four system. After TC Debbie had dissipated, survey teams from James Cook University (JCU) and Geoscience Australia conducted post-disaster damage surveys to assess the extent of damage caused by the storm. Observations of wind speeds during TC Debbie were recorded at a number of Bureau of Meteorology automatic weather stations, as well as six mobile anemometers deployed by JCU prior to landfall. While these stations provide valuable measurements of wind speed at their locations, an estimate of the winds throughout the landscape is required to assign maximum wind speeds to the observed level of damage at each surveyed location. This relationship will be used to develop vulnerability curves for building stock in the affected region. These curves can assist emergency managers prepare for and respond to future severe wind events, through developing an understanding of the vulnerability of local building stock to severe wind events. We use the following workflow to develop a corrected, local wind field for TC Debbie: 1. Model the maximum wind gust over the lifetime of TC Debbie across the landfall region using the Tropical Cyclone Risk Model (TCRM); 2. Apply a correction for local wind factors, including topography, land cover, shielding and wind direction; 3. Validate the local wind field against observations; 4. Apply a correction based on the difference between the observed and modelled wind fields. The final wind field is a product of the modelled wind field, local and observational corrections to produce the best estimate of the spatial distribution of the maximum wind gust throughout the lifetime of TC Debbie. Poster presented at the 2018 Amos-ICSHMO Conference Sydney, NSW (https://www.ametsoc.org/index.cfm/ams/meetings-events/ams-meetings/amos-icshmo-2018/)