Natural disasters, number of events

A disruptive natural event that overwhelms local capacities to restore order, necessitating in a request to national or international level for external assistance; an unforeseen and often sudden event that causes great damage, destruction and human suffering. Though often caused by nature, disasters also have human origins. Wars and civil disturbances that destroy homelands and displace people are included among causes of disasters. Other causes are structural collapse, blizzards, drought, epidemics, earthquakes, explosions, fire, flood, hazardous material or transportation incidents (such as a chemical spill), hurricanes, nuclear incidents, tornados, or volcanoes.