A 5-year-old, wearing just socks and light clothing, carried an 18-month-old through subzero temperatures in the Yukon Flats of Alaska after the power went out at the home where they had been left alone, according to the authorities.

The power failure scared the older child, who then carried the baby to a home about half a mile away in Venetie, Alaska, on Tuesday, the Alaska State Department of Public Safety said in a statement on Friday.

At the time, the temperature was about 31 degrees below zero, officials said, and both children suffered unspecified injuries from the cold. It was not immediately clear how the younger child had been dressed.

The children are expected to make a full recovery, Ken Marsh, a department spokesman, said on Sunday.

To reach the remote community, which has a population of 166 and is nearly 150 miles north of Fairbanks in interior Alaska, troopers had to charter a plane, Mr. Marsh said.

“It took 12 to 16 hours for them to actually get there,” he said. “Fortunately, we were confident that the children were in good hands because a neighbor had taken them in and we had spoken with the neighbor.”

An investigation led to the arrest of Julie Peter, 37, who was charged with endangering the welfare of a minor, officials said.

Efforts to reach Ms. Peter were unsuccessful.

The investigation revealed she had “deserted” the children in her home with no adult supervision, officials said. It was not clear whether Ms. Peter was related to the children or if the children were related to each other.

Officials did not release the details of those relationships because the victims were minors, Mr. Marsh said.

Venetie experiences extreme temperatures throughout the year, but especially in the winter.

From November to March, the temperature typically dips below zero, and extended periods of temperatures of minus 50 to minus 60 degrees are common, according to the Tanana Chiefs Conference, an Alaska Native nonprofit that serves the 42 villages of interior Alaska.