A natural disaster is a sudden event with wide impact, brought about by forces beyond human control and that causes profound damage or loss of life. The term is often used to describe catastrophes caused by a variety of phenomena, such as earthquakes, flooding, volcanic eruptions, tsunamis, landslides, wildfires, hurricanes and tornadoes.

A calamity is a severe disruption of a community or society, at any scale, due to hazardous events interacting with conditions of exposure, vulnerability and capacity, leading to one or more of the following:

Unlike hazards which are potential threats, the term ‘natural disaster’ refers to actual events with unfavorable consequences. Consequently, the damage and suffering they cause is much more serious than those of a hazard, because it reflects the reality that a natural disaster has occurred and cannot be ‘controlled’ by humans. The effects of a natural disaster can vary widely depending on the location and type of the occurrence. However, there are certain common aspects to the psychological impacts of natural disasters, such as the distress felt by people who have been affected. This may result in anxiety, trouble sleeping and other depression-like symptoms for the survivors who are impacted by such events. In addition, research has shown that being exposed to one natural disaster can amplify the adverse psychological outcomes for people who are affected by subsequent ones. The reason behind this is that people who are impacted by the first disaster become more vulnerable to them in future.