Norwegian police say four skiers who went missing after an avalanche in northern Norway this week have most likely died.

Police spokesman Morten Pettersen says "we no longer have any hopes of finding anyone alive." He said a helicopter on Friday picked up two avalanche beacon signals from an area in Tamok valley, near the northern city of Tromsoe, that had been hit by an avalanche. The skiers included a woman from Sweden and three men from Finland.

Mads Gilbert of the University Hospital of North Norway told a news conference in Tromsoe that "it was impossible to survive nearly two days buried in snow."

A search-and-rescue operation was launched after Wednesday's 300-meter (990-foot) wide avalanche. The skiers were last heard from that day. Heavy snowfall and poor visibility on Thursday had hampered rescue efforts.