First, the island was there. Then, it was mostly gone.

Before Hurricane Walaka swept through the central Pacific this month, East Island was captured in images as an 11-acre sliver of sand that stood out starkly from the turquoise ocean.

After the storm, government officials confirmed the island, in the northwestern part of the Hawaiian archipelago, had been largely submerged by water, said Athline Clark of the National Oceanic and Atmospheric Administration. East Island is the second island to disappear in recent months from French Frigate Shoals, a crescent-shaped reef including many islets, Clark said.

Chip Fletcher, a climate scientist with the University of Hawaii who has been studying East Island’s natural history, said it comprises loose sand and gravel rather than solid rock. His team had just taken geological samples from the island in July. But a little more than a week ago, he said, he was alerted by government officials that it had mostly disappeared.

“From my experience in cases similar to this, I had just assumed that the island had another decade to three decades of life left,” Fletcher said. “It is quite stunning that it is now, for the most part, gone.”

Clark, the NOAA superintendent for the Papaha­naumokuakea Marine National Monument, which includes the French Frigate Shoals, said no one immediately realized the island, located 750 miles northwest of Oahu, had largely disappeared because it is so remote.

East Island, with its sandy composition, wasn’t much of a match for the storm in early October, which started off as a Category 5 hurricane and created large storm swells, Clark said.

Although experts cannot directly trace the shrinking of East Island to the effects of climate change, Clark said, it contributes to the strength and frequency of hurricanes like the one that overtook the island. Scientists say hurricanes will be stronger because warmer water provides more energy to feed them.

“The intensity and frequency of storms is likely to increase,” Clark said. “This is probably a forebear of things to come.”

In 2016, President Barack Obama more than quadrupled the size of the Papaha­naumokuakea national monument, turning it into the world’s largest protected marine area. Created by President George W. Bush a decade earlier, the monument is home to an estimated 7,000 marine and terrestrial species, a quarter of which are found nowhere else on Earth.

Charles Littnan, a conservation biologist with NOAA Pacific Islands Fisheries Science Center, said about 96 percent of Hawaiian green sea turtles, a threatened species, travel to the French Frigate Shoals to nest. About half used East Island, Littnan said.

The shoals are also home to more than 200 endangered Hawaiian monk seals, he said. Only 1,400 of the species remain in the state.

The animals dodged the worst effects of the hurricane, Littnan said, because it struck late in their breeding seasons. Most of the turtles had already left the island by the time the storm hit.

When the turtles return next year, they may try to find another island on which to nest, Littnan said.

But it is possible that East Island will resurface and the turtles and seals will return to their seasonal homes. In images of the island after the storm, Littnan said he could already see that some monk seals had returned and hauled themselves onto the 150-foot-long patch of sand that remained.

He added the island’s future was uncertain.

“We’ve seen islands disappear in the past and re-emerge,” he said. “And we’ve had islands that disappear and they’re gone 30 years later.”

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