Natural disaster is a catastrophic event caused by natural phenomena, such as landslides, volcanoes, tsunamis, tornadoes, hurricanes, earthquakes and floods. These events have major impacts and cost billions each year, causing death and destruction. The impact on society can be much more than just economic as the psychological effects of such an event are often far reaching and lasting.

Disasters are often unpredictable and unavoidable, but they are not random. The science of disasters includes prediction and prevention. For example, the volcanoes of Mt St Helens and Vesuvius were rumbling for weeks before their explosive eruptions. Disasters have been part of the human experience, and people have learned to live with them through risk taking and experimentation. But it is impossible to avoid these events entirely and even the most prepared communities are vulnerable to extreme events.

The definition of a natural disaster is an event that overwhelms a highly vulnerable community and causes substantial mortality, morbidity and resource depletion. There are many factors influencing the severity of these events such as population density, methods of food and water access, poverty and type of governing bodies.

The term natural disaster is often misinterpreted as implying that the devastating results are inevitable and out of humans control, rather than being a result of a complex interaction between the physical world and societal structures built by humans. This view overlooks the role of human vulnerability and a failure to address the underlying causes that create these disasters.