The steel cylinder’s sudden appearance was first reported early Wednesday by a passerby who saw chunks of asphalt breaking off its surface. The bizarre sight baffled commuters and caused significant traffic disruption.

Witnesses told NHK they were stunned, with one office worker saying he “could not understand how it happened,” while another initially assumed a new road support had been installed overnight.

According to city officials, the pipe’s eruption scattered concrete debris beneath the elevated road but caused no injuries. At its peak, the 11.5‑foot‑wide pipe reached around 42 feet, forcing road closures in the busy district.

The incident occurred at a sewer construction site where crews had been connecting an existing sewer line to a new rainwater overflow channel. The pipe had been used as a retaining structure to prevent soil collapse. Officials believe that after workers drained water from inside it, the now‑empty pipe floated upward due to buoyancy.

Local resident Ryozo Kawakita told Japan Today he was unable to move his car because of the closures. “I can’t believe this,” he said.

By Thursday, firefighters had cut a hole in the pipe and pumped water inside, lowering it back to just a few feet above ground level. The city plans to remove the remaining 5.2 feet still protruding, a process expected to keep the road closed for several more days.