As Hurricane Dorian struck the northwestern Bahamas on Sunday, the National Hurricane Center said that the maximum sustained winds around the eye of the “extremely dangerous” storm had reached 185 miles an hour, making it a “catastrophic” storm with “devastating winds.”

Early Monday, after the eye of the storm had reached Grand Bahama Island, the winds had slowed slightly to 165 miles an hour. The center said further gradual weakening was forecast but fluctuations in intensity up or down could occur. By 6 a.m., the center warned that the storm would continue to linger over the island for hours and urged residents to stay where they were.

Early images and video emerging from the Abaco Islands, which were hit especially hard overnight, showed scenes of devastation as the powerful, slow-moving storm churned its way through the islands. The footage showed roofs torn from houses and cars and debris bobbing along inundated streets battered by strong winds and heavy rains.

Dozens of worried families posted pleas for information about their loved ones on social media after losing contact for hours at the height of the storm. The weather center advised people on the island to remain in their shelter until conditions improved, warning that could be several hours.