There was no snow or ice on the road surface in the area, about 180 kilometers (110 miles) northwest of Tokyo.

Most passengers were ski enthusiasts aged 18 into their early 20s, according to the Tokyo-based ski tour operator Keyth Tour. Packaged ski tours that come with overnight bus rides, lodging and lift tickets for around 12,000 yen ($100) are very popular among college students.
The injured were being treated at nearby hospitals. The Fire and Disaster Management Agency said 13 of the 27 passengers were seriously injured.

A male survivor, identified only as a college student, told broadcaster NHK that the bus swayed significantly before falling off the road, and he was stuck in a small corner when the bus finally came to a stop.

“I desperately tried to get out and struggled, and the next thing I remember is that I was outside,” he said.

The bus fell about three meters (10 feet) down the mountainside, Japanese media said.
Television footage showed the bus leaning against several trees as police investigators examined the wreckage while dozens of Japanese reporters and camera crew looked on from a distance. Police were to lift the bus and take it to the police station for further investigation, and Tokyo police are probing the bus operator.

The accident is the latest in a series of highway crashes in Japan involving tour buses that experts attribute to harsh working conditions for long-distance bus drivers. In some cases, drivers had fallen asleep at the wheel.

A fatal highway tour bus crash in 2012 that killed seven on their way to Tokyo Disneyland prompted some legal steps to improve driving safety, but accidents have continued. There were several last year, including one that involved two deaths and 26 injuries.
Chief Cabinet Secretary Yoshihide Suga said the transport ministry has set up a taskforce and dispatched officials to the crash site for investigation.