ANCHORAGE — As a Russian fuel tanker slowly moves through the frozen Bering Sea toward an iced-in city in western Alaska, it has been getting help from an unusual source at its destination: a drone that flies overhead and sends images of the sea ice to researchers onshore.

The camera-equipped drone looks like a smoke detector with wings and legs. It glides on 20-minute missions ranging from 10 feet to 320 feet above the ice, and its images can be instantly viewed on a tablet-type computer screen.

The tanker is bound for Nome, a town of 3,500 residents that missed its final pre-winter delivery of fuel by barge when a big storm swept the region last fall. Without the delivery of 1.3 million gallons, the city could run short of fuel before a barge delivery becomes possible in late spring.

Researchers were using the 2.5-pound drone to provide a large picture of the ice in hopes of guiding the tanker as close to shore as possible, said Greg Walker, unmanned aircraft program manager for the University of Alaska Fairbanks’ Geophysical Institute.

The Healy, the Coast Guard’s only functioning icebreaker, has been accompanying the 370-foot tanker through the Bering Sea.

Progress was stalled by thick ice and strong ocean currents on Tuesday. The vessels made nine miles but drifted with the ice while at rest for a total gain of just six miles, Coast Guard spokesman David Mosley said.

Ice conditions were slightly improved on Wednesday. The Coast Guard said the two vessels were in densely concentrated ice about 95 miles from Nome.

Meanwhile, a researcher assisting in the mission has discovered a 25-foot ice pressure ridge at the entrance to the Nome’s harbor.

The pressure ridges are created when the pack ice from offshore pushes against the stationary shore ice, creating thick ridges somewhat like icebergs, scientists said.

The top of the ridge sits about 5 feet above the frozen surface but the rest extends well down into the ocean, the Geophysical Institute’s Andy Mahoney said. The ridge is too big to get past but it shouldn’t prevent the tanker from offloading its fuel through its mile long hose.

Pictures from the drone will be used to figure out the best way to lay the hose.

As the tanker approaches Nome, the pressure ridges actually might come in handy as they are natural fault lines, Walker said. If the tanker can break the ice away from the ridges, it could open up a pathway.