Baltimore Key bridge collapse: New 3D images show wreckage underwater as salvage operation continues

New 3D images released by the U.S. Navy show the underwater wreckage of what was once the Francis Scott Key Bridge.

The U.S. Army Corps of Engineers in Baltimore posted the images online Tuesday. "These 3D images show the sheer magnitude of the very difficult and challenging salvage operation ahead," they said.

The images were supplied by the Navy’s Naval Sea Systems Command (NAVSEA) Supervisor of Salvage and Diving (SUPSALV) and show the twisted steel and concrete at the bottom of the Patapsco River.

READ MORE: Temporary channel opened for vessels clearing Baltimore Key Bridge wreckage

"The underwater sonar imaging tool, known as CODA Octopus, is the primary survey tool used by divers, with visibility clouded to just one to two feet because of the four to five feet of mud and loose bottom of the Patapsco River," the post continued.

The salvage operation calls for divers to work in virtual darkness. When lit, their view is compared to driving through heavy snowfall at night with the high-beams on, the post said.

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New 3D images released by the U.S. Navy show the underwater wreckage of what was once the Francis Scott Key Bridge. (Baltimore District, U.S. Army Corps of Engineers)

"So murky is the water, divers must be guided via detailed verbal directions from operators in vessels topside who are viewing real-time CODA imagery," the U.S. Army Corps of Engineers continued. "No usable underwater video exists of the wreckage, because as one Navy diver stated, ‘there’s no need take video of something you can’t even see.’"

The bridge fell early in the morning on March 26 after the crew of the massive container ship Dali lost control after a power outage. The ship’s crew issued a mayday allowing enough time for police to stop vehicles from continuing onto the bridge. However, the mayday call did not allow enough time for a construction crew of eight workers filling potholes on the bridge span to get off the structure.

READ MORE: Dali cargo ship owners seek to limit liability in Baltimore Key Bridge collapse

Two of the workers survived the disaster. Two bodies were found in a submerged pickup truck. Four more men are presumed dead. Weather conditions and debris from the wreckage have made it too dangerous for divers to search for their bodies.

The collapse of the iconic bridge completely blocked traffic along the vital port’s main shipping channel causing major economic and travel disruptions around the region and across the country.

A temporary channel near the bridge collapse site opened Monday, allowing some traffic to pass into the port. A tugboat pushing a fuel barge was the first vessel to use the alternate channel to bypass the wreckage. The channel will primarily be used by vessels that are helping with the cleanup effort.

Some barges and tugs that have been stuck in the Port of Baltimore since the collapse are also scheduled to pass through the channel.

Officials said they're working on a second channel on the southwest side of the main channel that will allow deeper vessels to pass.

The Associated Press contributed to this report