It was twilight Monday in Coney Island, the hour of the sea gull, and normally, the turning of the human tide.

At the boardwalk comfort station, families lined up to rinse the sand from their toes with a green hose, then hopped into flip-flops or sneakers. Bared to the early-evening breeze, the backsides of small children were given brisk rubs with damp, gritty towels. A mother leading her diapered toddler to a changing table suddenly realized that her other little ones were outside, unattended, so she shouted an assignment over her shoulder: “Alice! You got Julie and Jayson.”

On the boardwalk, Alex Flores hollered at his sons, Alex, 10, and Brandon, 7, dangling off the railing. “We just got the sand off you,” he said. “Cut it out.” He looked to the sky. “What time is the movie starting?” he asked.

The answer was in front of him: in a little while. Streaming down the boardwalk was a parade, of parents, babies in strollers, older people using walkers, and others, of every age in between. A tide was coming in, thousands strong, slowly and surely.