The 370-foot (113-meter) ship, hauling more than 1.3 million gallons (5 million liters) of fuel, is scheduled to arrive later Monday or Tuesday. It was less than 190 miles (305 kilometers) away on Saturday.
Video and still photo images released by the Coast Guard show the two vessels moving steadily through ice jammed seas.
"They’re navigating through ice right now, taking a direct route for now," said Jason Evans, the CEO of Sitnasuak Native Corp, one of the companies undertaking the delivery. "They considered going through patches where there might be thinner ice, but determined that that would have taken them on a longer route."