Widespread floods from Glomma River impact downstream regions after dam collapse, Norway
Heavy rains and strong winds affecting parts of Norway since August 6, 2023, caused widespread flooding, landslides, and a partial collapse of the Braskereidfoss power dam on the Glomma River. The country reportedly suffered the heaviest rains in 25 years.
In the aftermath of the heavy rains and strong winds brought by a low pressure system named Hans, central-southern Norway witnessed a series of cascading events. Over 5 000 individuals were officially evacuated from their homes, and there are suggestions that many more may have self-evacuated due to the immediate threat.
The situation was further compounded when the Braskereidfoss power dam on the Glomma River in Innlandet County partially gave way on August 9. This collapse has been attributed to the relentless rain and has subsequently caused significant flooding in the downstream regions.
Authorities initially considered blowing up part of the dam in an attempt to prevent communities downstream from being inundated by using a limited, controlled blast to release pressure on the dam.
However, that proposal was scrapped after water later broke through the structure, police spokesman Fredrik Thomson told reporters.
The dam’s generators stopped working early Wednesday after a power grid failure, plant operator Hafslund Eco said in a statement. According to official reports, an automatic system that should have opened the floodgates to release water failed. Rapidly rising water then spilled over the dam and into the power station itself, which caused major damage.
All people — at least 1 000 — living close to the river in the area were evacuated before the dam began to fail.
Multiple reports indicate that several landslides occurred during the rain event, disrupting transportation and daily life. As a consequence, a plethora of roads have been deemed impassable and numerous train routes in vast sections of southern Norway are no longer operational.
Given the severity of the situation, the Copernicus Emergency Management Service was swiftly activated on August 8 in rapid mapping mode (designated EMSR683) with the goal of providing an accurate damage assessment.
According to the Norwegian Water Resources and Energy Directorate, unprecedented flood levels have been observed at multiple locations in the Drammensvassdraget basin, situated west of Oslo.
Erik Hojgard-Olsen, a meteorologist from the Swedish Meteorological and Hydrological Institute, expressed to Aftonbladet that the current weather patterns are unusual for the season. “Experiencing a low-pressure system like Hans, which has consistently delivered heavy rainfall over consecutive days, is certainly extraordinary, particularly for a summer month,” he noted.
Weather predictions for the immediate future also contribute to these concerns. Over the upcoming 48-hour period, meteorologists expect southern Norway to receive moderate rainfall. Complementary to this, a series of weather warnings have been released, with red and orange alerts specifically highlighting potential flooding and a yellow warning flagging possible landslide events, all primarily concentrated in the southern regions of the country.
References:
1 Norway evacuates more people from flooded areas as rain ends – Reuters – August 10, 2023
2 Norway – Severe weather, floods and landslides – DG ECHO – August 11, 2023
3 Dam in Norway partially bursts after days of heavy rain, flooding and evacuations – AP – August 10, 2023
Featured image credit: NRK (stillshot)
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