The slow work of sifting through the remnants of a collapsed Florida building stretched into a sixth day yesterday .

“We have people waiting and waiting and waiting for news,” Miami-Dade Mayor Daniella Levine Cava said.

“We have them coping with the news that they might not have their loved ones come out alive and still hope against hope that they will.

“They’re learning that some of their loved ones will come out as body parts. This is the kind of information that is just excruciating for everyone.”

The work has been deliberate and treacherous.

Thunderstorms hit the area yesterday morning, and debris fell on to the search area overnight from the shattered edge of the part of the building that still stands.

Only two additional bodies were found on Monday, raising the count of confirmed dead to 11.

That leaves 150 people still unaccounted for in the community of Surfside, just outside Miami.

Authorities are meeting frequently with families to explain what they are doing and answer questions.

They have discussed with families everything from how DNA matches are made to help identify the dead, to how next of kin will be contacted, to going into “extreme detail” about how they are searching the mound, the mayor said.

Armed with that knowledge, she said, families are coming to their own conclusions.

“Some are feeling more hopeful, some less hopeful, because we do not have definitive answers. We give them the facts. We take them to the site,” she said.

“They have seen the operation. They understand now how it works, and they are preparing themselves for news, one way or the other.”

Rescuers are using bucket brigades and heavy machinery as they work atop a precarious mound of pulverised concrete, twisted steel and the remnants of dozens of households.

The efforts include firefighters and sniffer dogs.

Authorities said it is still a search-and-rescue operation, but no one has been found alive since hours after the collapse on Thursday.

The building collapsed only days before a deadline for condo owners to start making payments toward repairs that had been recommended nearly three years earlier, in a report that warned of “major structural damage”.