The global frequency of occurrence is the criterion used in this article to determine the most common natural disasters. The rankings are based on statistics from the International Strategy for Disaster Reduction (ISDR), an organisation headed by the United Nations secretary for humanitarian affairs. The statistics cover the years from 1970-2005. Flooding is the most frequent disaster in all parts of the world except Africa and Oceania, epidemics are more frequent in Africa, and windstorms are more frequent in Oceania.
Flood (30.7 per cent)
Flooded areas can be localised or cover a large area, and the speed of flood development can vary as well. They can develop slowly as when a river or stream grows beyond its banks during a period of days, or they can take the form of extremely dangerous flash floods. The leading cause of weather-related deaths in the United States, flash floods can occur in a few minutes, sometimes without any local indications of rain.
Windstorm (26.8 per cent)
This category includes hurricanes and typhoons that can devastate a huge area, and the more localised but equally devastating tornado. Forecasted global warming and the associated sea-level rise could make coastal areas more vulnerable to storms, and ISDR statistics show a marked increase in hydrometeorological disasters during the last 30 years.
Epidemic (11.2 per cent)
Most of us are familiar with global epidemics such as HIV/AIDS and H1N1 and with the more gruesome ones like Ebola. Typhoid and bubonic plague still cause problems in some parts of the world, and epidemics are the most frequently occurring natural disaster on the African continent.
Earthquake (8.9 per cent)
Geological disasters have shown a small but noticeable increase in frequency since 1975, and the human suffering and loss caused by earthquake-generated tsunamis during the first decade of this century are well known. Strong earthquakes can destroy even the strongest buildings, and even a mild earthquake can bring down poorly built structures like those found in poorer areas of the world.
Drought (7.8 per cent)
Drought is not a disaster that happens overnight, but it can be one of the most devastating. Droughts severely impact the economy, social structure and the environment.
Landslide (5.1 per cent)
Earth, rock and debris on slopes can be caused to flow by natural causes such as excessive rain and flood. They can also be caused by some human activities: grading, excessive development, etc.
Others Combined (9.6 per cent)
The final four most frequently occurring natural disasters account for less than 10 per cent of the total. They are Extreme Temperature (3.5 per cent), Wildfire (3.4 per cent), Volcanoes (1.7 per cent), and Insect Infestation (1.0 per cent)