Types of Disasters
In Queensland, most disasters relate to extreme weather events (floods, cyclones, droughts) and occur regularly. Events related to extremes of the the earth’s geology (earthquakes, tsunamis, volcanic eruptions) occur less frequently, but result in major consequences when they happen. Disasters are also commonly categorised by their origin - either natural or man-made, with most disasters being natural disasters.
Depending on exactly where you live, there may be several natural disaster types that are common. These have been highlighted below.
A cyclone is a violent storm characterised by high winds rotating about a calm centre of low atmospheric pressure that can produce winds in excess of 200 km/h which can cause extensive damage and result in death or injury caused by flooding, buildings collapsing or flying debris.
A flood is retention of water in the landscape due to excess rain that occurs in low-lying areas and/or near watercourses that can lead to water overflow. Flash floods can occur when a storm moves slowly, so that a small area receives most of the rain, but the drainage and runoff characteristics on the ground can also determine the area of greatest impact. (Remember, flood damage is not usually covered by insurance).
There are two types of severe storms: thunderstorms and land gales. Thunderstorms can produce hail, wind gusts, flash floods, tornadoes, and, lightning which can cause death, injury and damage to property. Thunderstorms are more common and generally more dangerous than land gales. Land gales are simply gale force winds that occur over the land.
Bushfire is one of nature’s most devastating forces. Your house does not have to back on to bushland to be at risk. Whether you live on an urban fringe area, semi rural or rural area you may live in a bush fire-prone area and need to be prepared. On a day of high bushfire risk you need to have a clear bushfire plan. Fire fighters urge residents to be aware of the risks and responsibilities in grass and bushfire-prone areas, and to prepare their properties for the fire season.
A heatwave can be defined as a prolonged period of excessive heat. In Australia excessive heat can vary from 37°C to 42°C. A heatwave occurs when there are a number of consecutive days with above average temperature, often combined with high humidity. This unusual and uncomfortable hot weather can impact on human and animal health and cause disruption to community infrastructure such as power supply, public transport and services.
A tsunami is a series of fast moving waves produced during large-scale ocean disturbances. A tsunami can occur with very little warning; caused by a variety of natural or technological events, such as earthquakes, volcanic eruptions, explosions, landslides, and meteorite impacts.
Earthquakes are a shaking or trembling of the Earth's crust caused by the release of huge stresses due to underground volcanic forces, the breaking of rock between the surface, or by a sudden movement along an existing fault line. Earthquakes are unpredictable and strike without warning. They range in strength from slight tremors to great shocks lasting from a few seconds to a few minutes.
A biological disaster may have a considerable impact in terms of human life, disability, quarantine, treatment costs and disposal of deceased persons in addition to long term environmental and economic consequences. It is important to recognise that biological disasters may be naturally occurring events (e.g. an influenza pandemic) or a deliberate event (biological terrorism).