Barry Cohen and his wife awoke to a thunderous noise in their Florida condo early Thursday, opened the door leading to their hallway and faced a huge pile of debris that blocked their path.

“At first it sounded like a flash of lightning or thunder,” the former vice mayor of Surfside and a resident of the collapsed building told reporters.

“But then it just kept on — steadily for at least 15 to 30 seconds — it just kept on going and going and going,” said Cohen, 63, adding that there had been construction for more than a month on the roof of the 12-story Champlain Towers South Condo, which suddenly collapsed at 1:30 a.m. Thursday.

“I couldn’t walk out past my doorway,” he said. “A gaping hole of rubble.”

Trying to escape, Cohen said, he and his wife tried to take stairs down to the pool area, only to find that door wouldn’t open, so they headed to the basement and found rising water there.

They returned upstairs, where they screamed for help.

“It must have been 20 minutes, it felt like a lifetime that we were still stuck in this apartment on the balcony,” Cohen told CNN, adding that he, his wife and another resident were eventually rescued from the balcony of his third-floor unit.

“When we were waiting for the firetruck to approach the building, the building was still shaking. It just seemed like it was very unsteady. And I just, you know, knowing how what it looked like outside my door, I thought that any minute, we could be that same pile of rubble,” he said.

Firefighters soon plucked them on a cherry-picker and lowered them to safety.

“I thought the whole building was going to just collapse. So once we were in the cherry-picker, a feeling of relief just came over me that was incredible that I survived this tragedy,” Cohen said.

“I thank them,” he added. “They had such a hard job. It’s amazing what they do. I’m always happy to be alive, but I’m even happier today.”

With Post wires