Riverine flooding differs between the coastal and inland areas of NSW. Generally, rivers east of the Great Dividing Range flow eastward towards the ocean, while rivers on the western side of the range flow westerly and then south-westerly.
In coastal river systems, flooding can be relatively quick, leaving little time for warnings and preparing. In western areas of the state, floods can take a long time to flow downstream and arrive in communities. These floods can leave vast areas of land flooded for weeks or months. Often there is time for people and communities to prepare, but there can also be a long time that these communities are impacted or isolated.
Unlike flash flooding where flooding may subside after a short period of time, riverine flooding can occur long after heavy rain and at great distances from the location of the rainfall. Vast areas of land can be flooded for weeks or months on end, and floods can take months to evaporate or travel out of the state.
In the situation of riverine flooding, individuals and households may need to consider long term supplies until floods subside.