Rescuers were using helicopters, drones and dogs on Thursday to scan unstable ground the day after a major landslide destroyed homes in a village close to the Norwegian capital of Oslo. At least 10 people were still unaccounted for and 10 others injured, local officials said.
An entire hillside collapsed overnight Wednesday in Ask, in the municipality of Gjerdrum, 15 miles northeast of the capital. Homes were crushed and buried in dense, dark clay that was still too unstable on Thursday for rescuers to access on foot, the Reuters news agency reported.
Temperatures below freezing and snowfall made efforts to shore up remaining structures and find the missing even more challenging, with some houses left teetering on the edge of the crater created by the slide. Several buildings fell over the edge on Wednesday.
Norway's Prime Minister Erna Solberg, who travelled to the village of around 1,000 people on Wednesday, described the landslide as "one of the largest" the country has ever seen.
"It's a dramatic experience to be here," Solberg told reporters, expressing particular concern for those still missing.
"The situation is still so unstable with the mud that it's not yet possible to do anything other than helicopter rescues," she added.
Norwegian media said that 700 people had been evacuated from their homes, and the municipality warned as many as 1,500 could need to leave the region out of safety concerns.
"We are still searching for survivors," Reuters quoted the head of the police operation at the site, Roger Pettersen, as saying, adding that children and adults were among those still missing.
Police said 10 people were injured, with one transferred to Oslo with serious injuries.
Pettersen said Wednesday that emergency calls had come in from people saying their whole houses were moving with them inside. Overnight helicopters used heat-scanning technology to search for people, and they lowered several rescuers onto structures as part of their efforts.
"There are dramatic reports and the situation is serious," Pettersen said.
According to the Norwegian Water Resources and Energy Directorate (NVE) what happened was a so-called "quick clay slide" of approximately 328 to 766 yards.
"This is the largest landslide in recent times in Norway, considering the number of houses involved and the number of evacuees," NVE spokeswoman Laila Hoivik told AFP.
Quick clay is a sort of clay found in Norway and Sweden that can collapse and turn to fluid when overstressed.
"The area has been surveyed earlier, and is known to contain quick clay. The possibility of similar large slides in the area is low at the moment," Hoivik said.
Reuters quoted Norwegian broadcaster TV2 as saying a 2005 geological survey had detected the clay and deemed the area unsuitable for residential development, but that new homes were built on the land just a couple years later.
Norway's king Harald said in a rare public statement that the accident had "made a deep impression" on him.
"My thoughts are with everyone affected, the injured, those who lost their homes and are now living in fear and uncertainty of the full extent of the disaster," he said.