SURFSIDE, Fla. — State Fire Marshal Jimmy Patronis said search-and-rescue teams faced a challenging mission while trying to find dozens of people who remained unaccounted for on Thursday in Surfside.

Shortly before 2 a.m., a portion of the L-shaped Chaplain Towers South partially collapsed. Fire Rescue personnel responded to the 12-story condominium building at 8777 Collins Ave. The rubble was in the northern part of the building.

Pancake effect Search-and-rescue experts said there was a pancake effect during a partial building collapse on Thursday in Surfside.

Neighbors said the collapse happened in seconds, it made windows shake and there was a white cloud of dust. Patronis said the “pancake effect” was wider on one side, so this is where the search-and-rescue teams accessed the area.

“But when you are entering the building through that wider end, it’s also up against the building that’s standing, you have that delicate balance of trying to make a way in safely,” Patronis said.

Structural engineers are helping with the search-and-rescue strategy. They are not excavating. Instead, they are using a parking garage that was under the building.

Rain caused some flooding. The teams are also dealing with the risk of the failure of the current structure or having other debris falling on them. Patronis said they are going in teams of 10 to 12 and the teams are taking turns.

“They only can work so long because it is heavy lifting and tough circumstances,” Patronis said.

Each team is tunneling through the debris and looking for signs of life. They have to be quiet so they can hear noises from survivors. Patronis said it’s exhausting work.

The building had more than 130 units and 55 were damaged, according to Miami-Dade Mayor Daniella Levine Cava. Most of them had serene views of the ocean or the intercoastal waterway.

Surfside Mayor Charles Burkett said there was ongoing roof work in the building, which was in the process of recertification. Structural inspections were required.

President Joe Biden’s administration is waiting for Gov. Ron DeSantis to sign an emergency order so the Federal Emergency Management Agency can step in to help.