Hazards, which can lead to disasters, can emerge from anywhere but many originate as a result of our natural environment.
Natural hazards are defined by UNDRR as:
Natural processes or phenomena that may cause loss of life, injury or other health impacts, property damage, loss of livelihoods and services, social and economic disruption, or environmental damage.
There are numerous types of natural hazards usually classified as:
These are weather related and can be directly associated with the weather event or occur as a result of weather events. They include:
Extreme weather events often match the hazards associated with typical weather systems but are usually considered more severe and an outlier in their frequency. For example, flash flooding caused by extreme rainfall will have many of the same outcomes of an average flood but either on a wider scale or with a more severe impact.
These are related to the physical processes within our planet, these hazards are often difficult to predict and can produce both slow and rapid onset events. They include:
In the chart shown in the figure below you can see that hydrometeorological events dominate as natural hazards that result in disasters. It is interesting to note that the frequency of each disaster type does not correlate entirely with the number of people affected, as you can see in the second part of the figure. We should also note that there is no simple correlation with the number of deaths caused by each disaster type.
Select image for enlarged view
Natural hazards can be characterised by their magnitude, speed of onset, duration, and spatial extent. Larger and usually rarer events tend to have the most impact.
Several disaster databases also include biological hazards within ‘natural hazards’. Such triggering events would include:
Consider your country, what natural hazards have occurred there?
Which are the most and least frequent hazards and which type has had the greatest impact?
UNISDR, (2016) Report of the open-ended intergovernmental expert working group on indicators and terminology relating to disaster risk reduction. Seventy-first session Agenda item 19 (c) Sustainable development: disaster risk reduction [online] available from https://www.preventionweb.net/files/50683_oiewgreportenglish.pdf [18 October 2019]
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