Risk carriers active in Southeast Asia and Japan are among those expressing interest in JBA Risk Management’s new worldwide flood model

Flood risk modelling boffins at JBA Risk Management have created a probabilistic global flood model, the company has announced. 

The first of its kind put together on a global scale, the model covers river and surface water flood across the whole globe (excluding relatively uninhabited Greenland and Antarctica) at 30 metres resolution. JBA’s US and European models operate at 5 metres resolution, but 30 metres is the best fit available globally, the company said.

“This is the first probabilistic global flood model,” said Jane Toothill, director, JBA Risk Management, told GR. “From a user perspective, this is the first time someone can import into a single model an entire international portfolio, which has risks across multiple continents, and analyse that in one go.

“The concept of an unmodelled flood territory goes away, from a client perspective, because it can immediately provide model results for any territory or region worldwide,” Toothill adds.

Biggest source of cat loss

She disputes flood being called a secondary peril – something with which many loss-hit underwriters might concur. Floods are the biggest overall source of catastrophe losses globally. What she does emphasise is that it is difficult to model compared to some other high-profile cat risks.

“What I would say is that flood is a high-resolution peril,” she says. “Property exposed to flood can be just metres away from another much safer property. Terrain and elevation have a strong impact in determining whether a property is at risk. That requires a highly detailed approach, demanding on data to be stored and analysed for a model to be run. That’s why traditional modelling companies have neglected flood for many years.”

She notes that hours clauses can be a particularly big variable for flood loss estimates, because river systems vary hugely in size. “UK river basins are relatively small, for example, so events come through quicker than they would on the Rhine or Danube which can take several weeks to rise from the source to the river’s mouth,” Toothill says.

UK-based JBA Risk Management was set up in 2011 and is part of the JBA Group – the world’s largest flood risk consultancy, with a track record of working with the water industry and the UK’s Environment Agency.


The company developed its latest global model using a combination of in-house and open source data and proprietary “FLY” technology, to include more than 15 million real and simulated hydrological events, with various insurance hours clauses, and disaggregation using population density from any geographic resolution.

“The global flood model is first to use the new FLY software we’ve created,” says Stephen Hutchings, JBA Risk Management’s head of modelling. “FLY is a set of components and individual tools to run cat models in a more modular way.

FLY not only enables risk quantification for any location across the world, but also removes the rigidity of traditional flood models by eliminating the need to embed assumptions into the model.

“This new modelling approach enables users to investigate and customise every aspect of the model when analysing a portfolio, including the data, parameters and assumptions. If they prefer, users can, of course, choose to take JBA’s expert view of flood,” adds Hutchings.

Responding to ease-of-access demands, the new model supports the Oasis open source modelling platform, allowing flexibility and customisation with outside data sources.

After the simple lack of availability of flood models, Toothill notes lack of transparency as a common modelling complaint.

“If users are to develop an in-depth understanding of a model, they need the ability to adjust the parameters and data behind it to see the difference those can make to results,” she adds.