What Turns a Hazard into a Disaster

Three factors determine the risk of damage when a hazard hits.

First, the characteristics of the hazard itself. Is it a flood, drought, hurricane, or heatwave? What’s its magnitude, speed, or power? And how long does it last? Is it a 30-minute downpour or a 5-day deluge of heavy rainfall?

Second, the number of people or the amount of infrastructure exposed to the hazard. Does the earthquake strike a densely populated city or a rural area? How many people live on a coastline inundated by storm surges or sea level rise? How much stuff — buildings, bridges, roads, and other infrastructure — is in harm’s way?

Third and finally, the vulnerability of those who are exposed. A heatwave in Dubai will be less harmful than one in New Delhi because most people in Dubai have air conditioning. A strong earthquake in a country with quake-resistant infrastructure will be less damaging than the one that struck Haiti in 2010. Vulnerability is often strongly linked to income: poorer countries and communities tend to have fewer resources to protect themselves and respond afterward.

Disaster risk, then, sits at the center of all three. An increase in any of these dimensions increases the risk, while a reduction lowers it.

This is why you might hear the phrase, “There’s no such thing as a natural disaster”. Hazards only become disasters when they impact societies and people. A hurricane, for example, is not a disaster until it hurts or kills people or destroys homes in its path.