Natural hazards are natural events that can hurt people or damage places, like earthquakes, volcanoes, tsunamis, floods, erosion, landslides, storms, and droughts. They only become hazards when they affect where people live, work, or travel.
A “hazard” is the dangerous natural event itself, while “risk” is about what that event could do to people and the things they care about. Risk comes from three things together: the hazard, what is in its way (exposure), and how easily it can be damaged (vulnerability).
Key words
Consequences
What happens because of a hazard, such as damage to homes, roads, nature, or people’s lives.
Exposure
The people, buildings, roads, and other things that are in places that could be hit by a hazard.
Vulnerability
How easily people or things can be harmed, and how well they can cope and recover.
Likelihood
How likely a hazard is to happen; for example, a “1 in 100‑year” flood has a 1% chance each year, which is called a 1% Annual Exceedance Probability (AEP) and is also known as a 1 in 100‑year Average Recurrence Interval (ARI).
Risk
The overall danger, based on how likely a hazard is and how serious the consequences would be. Risk can be described as low, medium, or high, depending on how likely an event is and how serious the consequences could be.
Residual risk
The risk that remains even after protection, for example, if a flood is bigger than what a stopbank was built for.
