HACKENSACK, N.J. -- A glass canopy attached to a high-rise condominium building fell onto a parking garage two stories below on Friday, partly flattening the structure and trapping at least one person, authorities said.

Rescuers could see the victim but couldn't get to the person because they were concerned about the possibility of another collapse at the three-story garage, Hackensack fire Lt. Stephen Lindner said. They could not determine the victim's condition.

Authorities were checking out reports that two to three more people might also be trapped, Lindner said.

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The garage pancaked when the canopy fell on it, damaging vehicles. The top of the underground garage, level with the street, was littered with dirt, debris and glass, and the pavement split into chunks.

Rachel LaValle, 26, said she was driving out of the garage and had reached the street level when she noticed a cloud of thick white dust. Mistaking it for smoke, she got out of her car to check for a fire. Then, seeing through the dust to the part of the garage that had collapsed, she got back in her car, shifted it into reverse, parked and ran out of the garage.

She saw water spilling out of pipes and a big hole where part of the garage had once stood.

"There was still dirt coming down at me," she said.

It's unclear why the canopy fell from the 22-year-old building, which is adjacent to the garage. Several residents said workers had uprooted a tree between the street and the building within the past few months, and that a leak in the basement was being fixed.

Resident Chris Baldo was in his first-floor unit when he felt the building shake. He looked out his window and the garage "was just gone," he said.

Irene Casapulla, who lives on the second floor, said she heard "a bunch of thumping, and all of a sudden it sounded like an earthquake."

Emergency workers were helping residents leave the building as a precaution. One firefighter was wheeling a luggage cart stacked with cases of water for emergency workers out in the 90-degree heat.

Tax records show the condo tower was built in 1988. Equity Residential Properties of Chicago bought in 1998 for $36.3 million.

Marty McKenna, a spokesman for Equity Residential, said the building owner did not have much information yet about what happened.

"We're trying to let the fire department do what they do," he said.