June's summer solstice brought long hours of sunlight, and by mid-month images taken from NASA's Terra satellite showed the open-water area off the Alaskan coast had expanded substantially and snow had melted on land, a NASA release reported.
The rapid melt north of Alaska was part of a larger phenomenon as sea ice across the entire arctic reached record-low levels for this time of year, the National Snow and Ice Data Center reported.
"Recent ice loss rates have been 100,000 to 150,000 square kilometers (38,600 to 57,900 square miles) per day, which is more than double the climatological rate," the center said.
The Beaufort Sea was a "hot spot" of rapid retreat in June, researchers said, driven by a high-pressure pattern over the region that kept skies clear at the very time of year when sunlight lasts the longest.
The early onset of the spring melt and the sunny skies around the solstice have increased the likelihood of heightened melt rates throughout the rest of the summer, they said.