Flood warning system in place in Denmark – successful collaboration between DMI and SMHI
For three years, SMHI has supported our sister authority DMI in Denmark in developing a Danish warning system for flooding in lakes and rivers. The initiative has now reached a major goal with the launch of a system that has already been useful in connection with the extreme rain that occurred in July 2025, just weeks after the system was put into operation.
The Danish Meteorological Institute DMI, is SMHI’s sister authority in Denmark. SMHI and DMI have collaborated within meteorology and oceanography for many years, which in recent years has been extended to include hydrology and flood early warning. In 2022 DMI was designated as the national authority for flood warnings by the Danish government, to increase preparedness and reduce damage from flooding. To provide flood warnings for the Danish rivers and lakes, a hydrological model and river flood warning service needed to be put in place. In this work DMI has received support from SMHI, among others.
“DMI has made a fantastic progress in a short time and now have a functioning flood warning service that covers the entire country. The model used is based on SMHI's hydrological model HYPE, which has been adapted to Denmark,” says Jafet Andersson, who has been leading SMHI's efforts in the collaboration.
First live application shortly after introduction
Just weeks after the flood system was put into operation, it was used under real conditions to send out warnings to the public.
“It was an unusually heavy rainfall in July 2025, corresponding to a red precipitation warning in Denmark, which caused a risk of flooding in many places. The system accurately captured the situation, which for the first time enabled DMI to issue a category 1 river flood warning to key stakeholders, who in turn took action to reduce damage to society”, says Jafet.
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Unusually heavy summer rain over large parts of Denmark in July 2025 caused a risk of flooding in southeastern Denmark. The image on the left shows high probability of heavy rainfall predicted to fall on July 22–23 (map from DMI). The image on the right shows the flood warning for rivers that was issued to Danish emergency services and the public via the DMI website. Source: DMI
A major goal reached, collaboration continues
The official collaboration between SMHI and DMI to develop the forecasting and warning system has now come to an end. However, the positive experiences have inspired continued dialogue and collaboration between the authorities in new forms. Michael Butts, senior hydrologist at DMI, says:
“The contributions from SMHI through our close collaboration has had a major impact on the rapid development of the new flood warning system in Denmark. SMHI has been an invaluable sparring partner not only for hydrology and flood forecasting but also for the communication of warnings, warning procedures, visualizing data, forecasts and flood risks, sharing their experiences not only of what works but also what doesn’t. We are looking forward to continuing this fruitful collaboration in the years to come.”
Happy project team at the closing meeting in Copenhagen, October 2025. From the left: Peter Berg, SMHI, Maggie Henry Madsen, DMI, Raphaél Payet-Burin, DMI, Michael Butts, DMI, Niclas Hjerdt, SMHI, Charlotte Agata Plum, DMI, Cecilie Thrysøe, DMI, René Capell, SMHI, Jafet Andersson, SMHI and Jonas Wied Pedersen, DMI.
