(CNN) A nine-day heat wave scorched Antarctica's northern tip earlier this month. New NASA images reveal that nearly a quarter of an Antarctic island's snow cover melted in that time -- an increasingly common symptom of the climate crisis.

The images show Eagle Island on the northeastern peninsula of the icy continent at the start and end of this month's Antarctic heat wave. By the end of the nine-day heat event, much of the land beneath the island's ice cap was exposed, and pools of meltwater opened up on its surface.

Antarctica experienced its hottest day on record earlier this month, peaking at 64.9 degrees Fahrenheit. Los Angeles measured the same temperature that day, NASA said.

In just over a week, 4 inches of Eagle Island's snowpack melted -- that's about 20% of the island's total seasonal snow accumulation, NASA's Earth Observatory said.

"I haven't seen melt ponds develop this quickly in Antarctica," Mauri Pelto, a geologist at Nichols College in Massachusetts, told NASA's Earth Observatory. "You see these kinds of melt events in Alaska and Greenland, but not usually in Antarctica."