Flood season in Australia and across Livingstone Shire is between November and April.
There are three common types of floods that affect Australia.
A tsunami is a series of powerful, fast moving waves produced during a large scale ocean disturbance. Tsunami can occur with very little warning and are caused by a variety of events such as earthquake, volcanic eruptions, explosions or landslides
A tsunami is different from a wind generated surface wave on the ocean. The passage of a tsunami involves the movement of water from the surface to the seafloor which means its speed is controlled by water depth. Consequently, as the wave approaches land and reaches increasingly shallow water it slows. However, the water column still in deeper water is moving slightly faster and catches up, resulting in the wave bunching up and becoming much higher. A tsunami is often a series of waves and the first may not necessarily be the largest.
When a tsunami travels over a long and gradual slope, it allows time for the tsunami to grow in wave height. This is called shoaling and typically occurs in shallow water less than 100m. Successive peaks can be anywhere from five to 90 minutes apart. In the open ocean, even the largest tsunami are relatively small with wave heights of less than one metre. The shoaling effect can increase this wave height to a degree such that the tsunami could potentially reach an onshore height of up to 30 metres above sea level. However, depending on the nature of the tsunami and the nearshore surroundings, the tsunami may create only barely noticeable ripples.Tsunami Animation from an Undersea landslide
Geoscience Australia receives real-time data from over 50 seismic stations in Australia, and more than 120 international seismic stations. The seismic data are analysed by specifically designed automated systems to alert for potentially dangerous earthquakes. Expert seismologists then use the results of the automated process to quickly make a final analysis of the potential for the detected earthquakes to cause a tsunami. The analysis is immediately transmitted to the Bureau of Meteorology.
Equipped with the seismic information from Geoscience Australia and the Bureau's scientific tsunami modelling, specially trained staff at the Bureau then issue a warning that is in keeping with the threat level. JATWC continuously monitors all the relevant real-time sea-level observations to verify whether a tsunami has been generated and whether it is moving along the predicted path, and to provide timely updates of warnings. The JATWC is leading the world by providing warnings for Australia that identify not only affected coastal regions, but also whether the tsunami has the potential to cause inundation to low-lying coastal areas with need for major evacuation (land threat), or whether it is confined to dangerous rips and currents and some localized overflow onto the immediate foreshore with no need for major evacuation (marine threat).
The Bureau issues advice and warnings on any identified tsunami threat to emergency agencies, relevant authorities, media and the general community using the the same systems and infrastructure as used for warnings of other hazardous events such as severe weather.Be Prepared!