What can we learn from past storms?
- DynamicFlood
In the summer of 2011, Copenhagen in Denmark came to a standstill as heavy rainfall flooded streets, railways, and basements. A decade later, Gävle in Sweden faced a similar fate when an exceptional cloudburst shut down schools for months. These are examples of events that remain imprinted in local memory due to their dramatic impacts and the lessons they hold about how cities can cope.
Yet, when it comes to planning for the future, we tend to rely mainly on statistical rain scenarios rather than real historical events. But what happens when these two perspectives, predictive modelling and lived experience, are combined?
We have recently added historical rain events - meaning measured rain data from recent extreme rainfalls- into DynamicFlood. Therefore, you can now, next to statistical rain events, choose to run some real-world scenarios for more insight into how floods build up and how planned measures may reduce flood damage.
Sara Lerer, Head of Hydrology, explains:
“We have integrated historical rain event data into DynamicFlood to make it easier for engineers and planners to simulate flooding with events that actually have happened, not only with synthetic rains. We hope that this will give DynamicFlood users a deeper insight into how rainfall occurs and help make more robust decisions on how to plan our cities”.
"Users can also adjust key parameters to tailor the rain to their specific project. This makes it easy to explore targeted worst-case scenarios and design more resilient solutions.”
Sara Lerer, Scalgo
From “what-if” to “what actually happened”
Statistical rain events are synthetic rains that we generate using mathematical models to represent the worst case for a given return period. These events are often referred to as, for example, a “100-year event”. They are created to show a “what-if” scenario and they are crucial for planning and designing infrastructure that can withstand extremes.
In DynamicFlood, these events are built from the best available rain data in each country. Often Intensity-Duration-Frequency (IDF) curves produced by national authorities, based on decades of rain gauge records, are used to develop these synthetic rains.
"We hope that this will give DynamicFlood users a deeper insight into how rainfall occurs and help make more robust decisions on how to plan our cities."
Sara Lerer, Scalgo
You can choose and compare various rain events in Scalgo Live.
“We have put a lot of effort into creating these events and to ensure that they reflect local hydrological realities,” Sara continues, “and users can also adjust key parameters to tailor the rain to their specific project. This makes it easy to explore targeted worst-case scenarios and design more resilient solutions”.
In contrast, historical events show “what actually happened.” In DynamicFlood, we have selected the most damaging storms from recent years, and they give a realistic picture of how extreme rains occur. Because these events are well known to both the public and professionals, they serve as familiar reference points for understanding resilience.
So far we have added the following rain events:
Copenhagen, Denmark, 2011
Malmö, Sweden, 2014
Montpellier Fréjorgues, France, 2014
Kristiansand, Norway, 2018
Gävle, Sweden, 2021
Tjøme, Norway, 2021
Tende, France, 2020
Esbjerg, Denmark, 2024
With a combination of the predictive power of statistical scenarios and real-world lessons, you can now use DynamicFlood to test your projects and plans against both past storms and future extremes. Explore the historical rain events in DynamicFlood, and see how your projects stand up to some of the most extreme storms on record.
Do you know a rain event that you would like to add to DynamicFlood? Let us know - we would be happy to extend the list!
