A dam in Norway has partly collapsed as the country battles record high river levels, flooding and landslides after a fatal storm. Norwegian police were considering blowing up the dam when water from the Glåma River, the country’s longest, started spilling out the side at Braskereidfoss hydroelectric power plant. It comes after a powerful storm – named Hans – that has caused chaos across northern Europe in recent days, and left southern Norway in crisis after widespread flooding and landslides. River levels expected to continue rising into Thursday. A woman in her 70s died on Wednesday after falling into a stream and 700-800 people were evacuated from Innlandet, the district which also includes Braskereidfoss. All main roads between Oslo and Trondheim were closed on Wednesday. Pål Erik Teigen, chief of staff at Innlandet police district, said his force had been monitoring the Braskereidfoss dam and working with power plant owner, Hafslund Eco. “On the south-west side the water is starting to go through … it’s going slowly. This is the best thing now,” he told the Guardian. They had been considering staging a controlled explosion but once the water started coming through the side, they decided the best solution was to leave it. “It’s a very heavy situation we have in this part of Norway in the last days because of the rain. If I made a training exercise for the police I wouldn’t in my wildest dreams think of this problem in our district, he said. “We have many landslides all over, we have homes being taken, evacuated a lot of people, all the roads are closed and all the rivers are overflowing.” “It’s a big crisis for us. I’ve never seen anything like it,” he added. Hafslund said a fault at Braskereidfoss resulted in water getting into the power plant, which consists of two large turbines and a dam with floodgates. The company said in a statement: “The water has now passed through the filling dam, which is located next to the power plant. For the time being, it appears that the water diversion through the fill dam is going well. “There are large amounts of water in Glåma as a result of the storm Hans, and several different measures have been considered to ensure that the water is diverted past the power plant, including blasting. It is currently considered that it should not be blown up. “We are following the situation closely and are considering ongoing measures in collaboration with the police and defence on site.” The government hydrology institute, NVE, said parts of eastern and central Norway were still on red alert, with many rivers at record levels. “In a lot of rivers and lakes the level is still increasing,” said hydrologist Tuomo Saloranta. The Norwegian prime minister, Jonas Gahr Støre, who visited affected areas, said a huge challenge lay ahead. “When the rain stops, another challenge begins: the water needs to get out,” he said.