In the first instance the severity of this exposure is classified according to where the land parcel is in terms of building code requirements, first introduced in 1984. Australian Standard AS1170 identifies regions within Australia that are likely to experience cyclonic winds of different strengths. Builders are required to construct buildings in each of these different zones in a manner that prevents building failure. MyHazrds also calculates the probability of a cyclone passing within 50km of the location, based on cyclone paths from the last 109yrs. Lastly, the application takes into account severity and intensity data produced by the CSIRO.
Myhazards provides an indication of the first flood frequency that may inundate the land parcel. For the majority of land parcels in Australia there is no exposure to riverine flooding. For those with a flood exposure the ratings are Extreme (5% probability), Very High (2% probability), High (1% probability), Low (Rare, maximum flood). If depth of flooding for the predicted event is available it will be provided.
We rely upon data from local and state governments to determine the probability of flooding. If a government hasn’t updated data then the data used will not be the most accurate available. If a government has not provided data at all then the insurance industry must rely upon alternative sources to make decisions or use historical assumptions.
Potential bushfire exposure is based upon either designated BushFire Prone Land (BFPL) or where that has not been made available, distances from vegetation. It is not based on Bushfire Attack Level (BAL) which requires a highly specific calculation based upon multiple factors for an individual site. This exposure information should only be used to determine if you should make further and more detailed inquiries as to the precise risk at a location, after taking into account all factors including slope, orientation, vegetation type etc. All states except Victoria publish Bushfire Prone Land information to assist communities to make safer decisions.
Storms create damage from high winds and stormwater flows. The simplified exposure information in MyHazards is based on BoM data for the average number of thunderstorms in the location annually. The information provided also includes an estimate for the volume of rainfall predicted should the 1% probability (100yrs) storm occur in the location and last for 24hrs. The higher the volume, the more likely that buildings will suffer some type of stormwater impact.
Also known as ‘Storm-surge’ or ‘Actions of the Sea’, for the purposes of MyHazards this exposure is based on two simple factors, distance from the coast and elevation above sea level. In this application only properties within 1000m of the coast and below 5m in elevation are considered to have an exposure. This is a very simplified expression of the hazard and anyone living close to the coast at low elevation should review more accurate data produced by their local government, which will take into account a range of more precise factors.