Police have opened an investigation into the group that organized a mountaineering lesson during which seven high school students and a teacher were killed by an avalanche at a ski resort in Tochigi Prefecture, investigators said Tuesday.

The police will assess whether sufficient steps were taken to ensure the safety of the students taking part in the program.

Although the lesson originally was intended to teach mountain climbing, it was changed to deep snow traversing due to weather conditions at the site by teachers on location. Tochigi Prefecture’s high school athletic federation was unaware of the change, a senior official of the organization said.

The federation also did not have prior information on the exact training plan nor the names of participating students.

Kenichi Hashimoto, chairman of the athletic federation, said, “we must reflect on our crisis management. We will look into past training sessions as well.”

The investigation appears to be focused on the reason the group went ahead with the training despite heavy snowfall overnight and an avalanche advisory warning having been issued for the region.

The police will question the teachers and others for professional negligence resulting in death and injury.

Seven boys and one teacher from Tochigi Prefecture’s Otawara High School competitive mountain club were crushed to death in the incident Monday. It was one of the nation’s deadliest avalanche disasters in decades.

The eight victims are Atsuki Takase, 16, Yuzuru Asai, 17, Minoru Ogane, 17, Masaki Oku, 16, Hidetomo Hagiwara, 16, Yusuke Kaburagi, 17, Kosuke Sato, 16, and Yusuke Ketsuka, a 29-year-old teacher.

The snow on the slope appears to have slid about 100 to 200 meters. Rescue workers on Tuesday flew drones over Nasuonsen Family Ski Resort to assess the size of the avalanche and the extent of damage.

The avalanche advisory was issued around the ski resort after the area experienced over 30 cm of snowfall overnight through early Monday.

Some experts pointed out that the snowslide was likely a surface avalanche, where a layer of new snowfall slides over packed deposits of old snow.

According to a rescue worker who took part in the search effort, the students said the avalanche occurred during a break from training and that they did not have avalanche beacons, which send out radio signals to help locate people trapped under the snow.

Forty others were hurt in the incident — seven of which sustained serious injuries. A total of 51 students and 11 teachers from seven high schools were taking part in the three-day program.

Prime Minister Shinzo Abe said at Tuesday’s Diet session that the government will investigate the cause of the accident and strengthen disaster prevention measures.

According to the athletic federation, the climbing lesson has been conducted at the ski resort every year since 1963 and has been led by teachers of participating high schools who are also seasoned climbers.

In recent years, the person in charge of the annual event has been a teacher who is a licensed alpine climbing instructor and manager of one of the high school mountain clubs.

On Monday evening, a 16-year-old student told reporters at a hospital where he was taken after he was rescued that he heard someone shout “Avalanche!” but cannot recall the moment of impact because he was “too scared.”

“I was buried in snow up to my chest before I knew it,” he said. “I thought ‘I’m saved,’ when I found my head was above the snow.”

KEYWORDS tochigi, avalanche