A powerful storm has brought destruction to Norway, causing landslides and leaving an entire town stranded, as meteorologists warned of the strongest rainfall in a quarter of a century. The storm – named Storm Hans – has killed two people, ripped off roofs and caused widespread disruption across northern Europe in a summer that started with wildfires across much of the region. The Norwegian meteorological institute issued a red danger warning – the highest level of risk – on Tuesday for extremely heavy rainfall across parts of southern Norway. “In many places, the event will be among the strongest in the last 25 years,” it warned. On the east coast, north of Oslo, in parts of western Norway and the southern part of Trøndelag, as much as 80-100mm of rain in 24 hours was forecast. “Most counties in southern Norway will be affected to a greater or lesser extent,” the institute said. The danger warning was in place from Monday morning until Tuesday evening. Strong winds and rain continued across the region, also causing disruption, cancelling ferries, delaying flights, uprooting trees, flooding streets and also causing outages across Denmark, Estonia, Finland, Latvia, Lithuania and Sweden. In Oslo, people were urged to work from home and to avoid unnecessary journeys. In Valdres, some residents had to be airlifted by helicopter after there were several landslides. In the village of Bagn, Norwegian broadcaster NRK reported that a house and garage had been destroyed after a landslide hit a housing estate, and authorities warned there could still be further incidents. And in Asak, about 1,000 residents were completely cut off from the outside world by flooding. The only route remaining was reportedly a forest path along which food supplies will have to be delivered. The Norwegian prime minister, Jonas Gahr Støre, said on Monday night that it was “a very serious situation”. He added: “We see floods and destruction. There is reason to expect that this will last another day.” Text messages were sent out to tourists on holiday in the country warning them about the weather. The Norwegian water resources and energy directorate warned of “extremely heavy rainfall” in the south of the country. “Unnecessary traffic should be avoided,” it added. On Monday a 50-year-old woman in Lithuania and a man in Latvia were killed by falling trees. In central Sweden, a train was partly derailed owing to a washed-away embankment, injuring three. Elsewhere in Sweden, there were reports of chaotic scenes around Åre, a ski resort, where much of the town was flooded after a river burst its banks. The Swedish meteorological and hydrological institute issued a red warning for Halland and parts of Småland for Tuesday and Wednesday. The institute said Hans had also brought in warm air across the north, leading to tropical nights in multiple locations in Norrland. On Tuesday, Haparanda recorded a temperature of 30.2C – its highest August temperature since 1969. Meanwhile, in Estonia, nearly 10,000 people were left without power. In Denmark, waves of up to eight metres were reported and beach houses were washed into the North Sea. In Finland, authorities urged people to reconsider whether they needed to go out to sea.