SURFSIDE, Fla.—Search and rescue workers have recovered four more bodies at the site of the collapsed Champlain Towers South condo building, part of which was demolished in a controlled explosion Sunday night, but officials said they remain hopeful that access to crawl spaces in a newly accessible part of the rubble pile could still lead to survivors.

The operation was slowed Monday by high winds and lightning from Tropical Storm Elsa, but the search and rescue team now has access to the entire site. There is more heavy equipment and manpower on the field than at any time since the operation began 12 days ago, said Surfside Mayor Charles Burkett.

“We will continue 24 hours a day for the indefinite future until everybody is pulled out of that site,” Mr. Burkett said at a news conference Monday evening.