The Bering Air Caravan, a single-engine turboprop, was heading from Unalakleet to Nome on Thursday afternoon with nine passengers and a pilot, according to Alaska’s Department of Public Safety.

Authorities were working to determine its last known coordinates.

Unalakleet is a community of about 690 people in western Alaska, about 240 kilometres southeast of Nome and about 640 kilometres northwest of Anchorage.

The disappearance marks the third major incident in US aviation in eight days.

The Cessna Caravan left Unalakleet at 2.37p.m, and officials lost contact with it less than an hour later, according to David Olson, director of operations for Bering Air.

The aircraft was 19 kilometres offshore, the U S Coast Guard said. It was operating at its maximum passenger capacity, according to the airline’s description of the plane.

“Staff at Bering Air is working hard to gather details, get emergency assistance, search and rescue going,” Olson said.

Bering Air serves 32 villages in western Alaska from hubs in Nome, Kotzebue and Unalakleet.

Most destinations receive twice-daily scheduled flights on a Monday through to Saturday.

Airplanes are often the only option for travel of any distance in rural Alaska, particularly in winter.

The Nome Volunteer Fire Department said in a statement on social media that ground crews were searching across part of Alaska’s western coast, from Nome to Topkok.

“Due to weather and visibility, we are limited on air search at the current time,” it said. People were told not to form their own search parties because the weather was too dangerous.

In an update early on Friday, the department said that “crews are still searching on the ground, canvassing as much area as possible,” but that “we do not have any updated information on the location of the missing aircraft.”

A US Coast Guard airplane crew was expected to search the missing aircraft’s last known position.

The National Guard and troopers were also helping with the search, the fire department said.

It was minus 8.3 Celsius in Unalakleet around takeoff, according to the National Weather Service.

There was light snow falling and fog.

The names of the people onboard weren’t yet being released.

Nome, a Gold Rush town, is just south of the Arctic Circle and is known as the ending point of the 1,610-kilometre Iditarod Trail Sled Dog Race.

Alaska’s U S senators, Lisa Murkowski and Dan Sullivan, issued statements about the missing plane on X, saying their thoughts and prayers are with the passengers, their families, rescuers and the Nome community.

US Rep. Nicholas Begich posted on X that he was ready to assist the community of Nome and Alaska Gov. Mike Dunleavy ” in any way we can.”