There are tens of thousands of large dams worldwide and millions of kilometres of defences protecting people from floods. Although the chance of one of these failing is relatively low, the consequences can be deadly. In 2019, the failure of the Brumadinho tailings dam in Brazil led to around 300 fatalities.
Planning for these catastrophes in advance can help authorities to understand where the risks to people are the highest, and help to reduce the number of fatalities. Even issuing a warning a few minutes before a dam breaks or a major flood occurs can save a significant number of lives.