Public Safety Director Fritz Frage said the collapse happened at 333 Park Ave., impacting more than 60 residents.
The damage was so bad, gaping holes could be seen in the ceiling of the four-story apartment building. The higher the floor, the worse the damage.
One resident told Eyewitness News reporter Lucy Yang that it was raining inside of the building.
"Really bad. You had to walk with an umbrella," said resident Marisol Thompson.
But the collapsed portions of the roof told only part of the problem. Tenants complained that there are a host of issues inside the building, from toilets that are not secure, to cockroaches and rodents. They say the walls and ceilings sweat whenever it rains and that there were cracks beforehand, but Sunday's storm broke the dam.
City officials have advised residents to refrain from entering the building until has been declared structurally sound.
Thompson says they were sent to an empty apartment elsewhere with two other families. They have no beds or toiletries.
Another resident complains he was directed to a hotel, then had to sleep in the lobby.
The American Red Cross has opened a temporary shelter in the gymnasium of First Avenue School, located at 214 First Ave., but not everyone is staying there. Frage said only about 22 residents accepted shelter at the location, where food and water were available.
Thompson says she is not sure where they will spend the night.
It's not clear yet when the source of the leak will be fixed.
In addition to Newark, the deluge from Sunday's storm swamped parts of New Jersey.
Storms swamp parts of New Jersey
The storms were powerful enough to bring traffic to a grinding halt. Hundreds of vehicles had nowhere to go on the Garden State Parkway in East Orange.
The New Jersey Turnpike Authority issued a travel alert for weather-related closures on the Garden State Parkway and New Jersey Turnpike. The water there practically swallowed half a dozen cars, including a state trooper's cruiser.
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