A massive sinkhole created commuter chaos in downtown Fukuoka in southwestern Japan Monday, when the entire width of a major 5-lane road caved in on itself. The sinkhole is thought to have been caused by underground work on a subway extension says travelandleisure.com.

The collapse began at around 05:00 local time (20:00 GMT Monday) near Hakata Station, the busiest in Fukuoka city in the southern island of Kyushu. According to bbc.com it began with two smaller holes that grew steadily until they formed one huge depression around 30m (98ft) wide.

Subway systems were disrupted and blackouts affected about 800 households. Meanwhile, much of the surrounding area was evacuated by authorities due to worries over further sinkholes and potential gas explosions. Fukuoka airport also suffered a brief blackout.

"The power was out all of a sudden and I heard a loud boom. I went outside and saw a huge hole," said a witness, speaking to the Japanese daily The Mainichi. Engineering work to extend a nearby underground train line may be related to the sinkhole's sudden appearance, city officials said.

The sinkhole collapsed near Hakata Station, the busiest in Fukuoka city in the southern island of Kyushu. It began with two smaller holes that grew steadily until they formed one huge depression around 30m (98ft) wide. At around 5 a.m. local time, leaving a hole about 65-feet deep and waking up nearby residents as it swallowed traffic lights and chunks of road, exposing the support columns of nearby buildings. There were no reports of serious injuries but it disrupted power, water, gas and transport links in the area. Broadcaster NHK reported that an elderly lady slipped on some stairs because of the power cut.

The city's Mayor Soichiro Takashima said the sinkhole was "unprecedented," adding that local government "will speed up its efforts to prevent secondary disasters and repair lifelines." Officials suspect the incident was linked to construction on a nearby subway line.