Hawaii's East Island is no longer on the map.

The island, located about 550 miles northwest of Honolulu, is part of a chain of small island groups in Papahānaumokuākea Marine National Monument. When the chain was swept by powerful storm surges from Hurricane Walaka earlier this month, East Island was submerged.

The island was uninhabited, but scientists are worried because it was a refuge for two of the most endangered animals in the world: the Hawaiian green sea turtle and the Hawaiian monk seal.

Almost 96% of Hawaii's green turtle population travels to the island chain, known as the French Frigate Shoals, for safe nesting during their breeding season, according to Chip Fletcher, an earth science professor at the University of Hawaii at Manoa.

The islands in that area are mostly tiny slices of sand and gravel sitting on top of a submerged, extinct volcano.

"Our understanding is that these islands are formed as sea level falls," Fletcher said. "Sea levels are rising right now so the fundamental basis for forming these islands no longer exists."

Fletcher says East Island may remain underwater partly due to climate change.

Hurricane Walaka was a powerful Category 5 storm with winds in excess of 157 mph. It was one of several big storms to barrel through the Pacific this year. Fletcher says warmer weather and warmer water have a lot to do with why storms are getting stronger. And it's likely we'll see other islands going underwater, too. (CNN)