Clio Dahyun Axilrod and her parents had joined the thousands of visitors on Sunday enthralled by the spectacular waves fueled by Hurricane Bill that were breaking off the Atlantic coast of Acadia National Park in Maine. But as one series of waves crashed off the rocky cliffs about 350 feet south of the popular Thunder Hole, the family, from New York City, recognized the danger, turned around and headed up a diagonal path toward the roadway. They were about 40 feet from the main road, Ocean Drive, witnesses told a park ranger, when a 20-foot-high swell exploded into the air, sweeping Clio, 7, her father, Peter J. Axilrod, 55, and five other people out to sea. Clio's mother, Sandra M. Kuhach, 51, was knocked to the ground and seriously injured. Officials said on Monday that 13 people were hit by the giant wave and admitted to Mount Desert Island Hospital in Bar Harbor, Maine. Four of those who were dragged into the ocean were able to make it out of the 55-degree water on their own, said a Coast Guard spokesman, Chief Petty Officer Christopher Wheeler. About an hour after the wave carried Peter Axilrod into the ocean, he was rescued by the Coast Guard in a 47-foot lifeboat. A 12-year-old girl, Simone Pelletier of Belfast, Maine, was also brought to safety by the Coast Guard and taken to Mount Desert Island Hospital with non-life-threatening injuries. But it took rescuers more than three hours to locate Clio, who was found unresponsive about a half-mile from shore. She died from drowning, the Maine Marine Patrol said Monday. Her parents remained hospitalized at Eastern Maine Medical Center in Bangor, a patrol spokesman said in a news release. The family lives on the Upper East Side of Manhattan, opposite Gracie Mansion. Neighbors on Monday described Clio as an energetic child who liked to swim with her friends in the rooftop pool of the 20-story building where the family lived. 'She was a very good swimmer,' said one woman who would not give her name. 'Very friendly, very talkative.' Another neighbor described the family as 'fabulous people' and Kuhach as a mother who 'spent her whole life developing this child and making her feel confident.' Acadia National Park's chief ranger, Stuart West, recounted on Monday how a sunny summer weekend day turned tragic. Earlier Sunday, park officials had closed off the paved walkway and a series of interlocking gates that led to viewing stations at Thunder Hole, an inlet with a submerged cave that is known to produce booming, plumelike waves. On Friday, signs warning visitors were posted there and on Sand Beach, just to the north. But West said that the bedrock path in the undeveloped area south of Thunder Hole was not closed. 'We didn't close off all the rock areas,' he said. 'I don't think there was a need for it. The fact that there was high surf, and the good weather, it was like a bug to a light. People were going to go no matter what.' Ten park rangers were on duty Sunday morning, he said, with others reporting throughout the day to monitor the conditions and the park crowd, which numbered about 10,000 throughout the day. 'If you close off an area, people are going to spill into another area,' West said. 'And if we keep those areas contained, and stack them full of rangers, that way we can have an immediate response, which is what happened.' West said he did not know whether a park ranger had warned the victims, and it was unclear if they had seen the warning signs in nearby areas. Park rangers learned from the Coast Guard, West said, that the waves, about 15 feet high, were arriving at 16-second intervals about two hours before high tide. The penultimate wave in the fatal series landed at the ankles of observers on the rocks. The one after that was unlike all the rest. 'Nature is forceful and unpredictable -- and it just moves us to pay close attention to where we are,' said West, who was at Schoodic Point, another beach on the mainland part of the park, when the accident occurred. 'You could tell people to step back, but they didn't register how dangerous the waves were.' 'All I can say,' he added, 'is that we do the best we can to educate the public. They are ultimately responsible for their safety and their family's safety.' 