SURFSIDE, Fla. — Rescue crews have dug a large trench through the rubble of the collapsed Surfside condo tower as they continue to search for possible survivors.

Crews used heavy equipment to dig the trench, which is described to be 125 feet long, 20 feet wide and 40 feet deep. It was created for two purposes:

One of the reasons is to let rescuers search for survivors in other parts of the pile with their dogs, cameras, sonar and infrared technology. It was also part of an effort to combat a “deep” fire that Miami-Dade County Mayor Daniella Levine Cava described over the weekend as “hampering” search efforts.

More about the Florida condo collapse

Levine Cava said the smoke was the “biggest barrier” for the search and rescue mission. She said crews worked nonstop under the rubble to stop it, using infrared red technology, foam, water and other tactics to contain the fire and minimize the smoke, which had spread through the pile.

The fire has since been extinguished and is “one less thing the men and women in the pile have to worry about now,” Surfside Mayor Charles Burkett told NBC6 early Monday.