First came the thunderous boom.
Then the street shook, and bricks, wood and glass rained down on Park Avenue. Thick, suffocating smoke quickly enveloped the residential block of East Harlem. Two five-story apartment buildings, including a street-level church and piano store, lay in rubble, with at least two dead and more than 50 injured. A fire, fed by leaking gas, burned inside.
Stunned witnesses ran for cover, some cut by the shattered glass. Others went inside to help victims get out. Some stumbled from the wreckage, covered in debris.
"It sounded like a bomb. That's what it really sounded like," Trey Dey, a laborer who was working in a nearby basement when the buildings exploded, told NBC 4 New York.
When he made it to the street, Dey said, he saw the crumbled buildings, people running about in the swirling smoke and dust, stunned. A few minutes later, he noticed the flames.
"I thought a train had exploded," said Marisa Aquino, who was at her apartment nearby, on 115th Street between Park and Lexington.
New Yorkers up to a mile away reported feeling the vibrations of the blast.
"It looked like something out of Beirut," said Christopher Grande, who ran to the scene from his nearby home.
The roof of one building looked like it was blown up from inside, he said, "like a party cake."
Rubble lay several inches thick on the ground, cars and on the roofs of nearby buildings. Some debris was blown onto the elevated tracks of the Metro-North commuter rail line above Park Avenue, causing a shutdown of service in both directions.
A woman who lives a few blocks from blast recalled watching TV when her apartment shook and her windows shattered. "I didn't know what it was," she said.
EMTs pulled victims out on stretchers and into ambulances. Some lay on the pavement getting treatment. Authorities ordered people who live in nearby buildings to leave, and the evacuation area was expected to expand, Community Board 11 chairman Matthew Washington said.
"We're trying to make sure everyone is safe," Washington said.
Amid the confused crowds who gathered at the scene were many worried about loved ones they feared were trapped inside.
"I want to know if my daughter is fine," one woman wailed. "Please help me."
A man who said his 42-year-old brother, George, lived in a fifth-floor apartment of one of the ruined buildings, waited for word.
"We just want to know if he's alright," the man said. "I just want him alive."
As they spoke, rescue crews were still searching for victims. Firefighters worked to extinguish the flames. Utility workers dug up the street to shut off gas mains.
The plume of white smoke continued to pour into the sky.