Seven students and one teacher from Otawara High School in Tochigi Prefecture died Monday after being caught in an avalanche at a ski resort during a climbing event in the town of Nasu, an official with the Tochigi Prefectural Police said.

The police official said 40 people were injured, adding that the department received an emergency call alerting it to the avalanche at Nasuonsen Family Ski Resort at around 9:20 a.m.

The incident occurred around 8:30 a.m., as 40 students and eight teachers were training to walk in the accumulated snow.

The town of Nasu received 33 cm of snow over an eight-hour period through 9 a.m. as of Monday morning, and avalanche warnings were in effect.

The ski resort concluded operations for the season last week.

The police are looking into whether the deaths resulted from professional negligence given the extreme conditions at the time the training was being conducted.

The Tochigi education board said 51 students in mountaineering clubs and 11 teachers from seven high schools were participating in the climbing lesson event that began on Saturday.

The board also said the students were scheduled to ascend the mountain on Monday, but the climb was canceled due to the heavy snow. Instead, the group practiced walking in the accumulated snow.

The training took place about 500 meters from their hotel at an altitude of 1,300 meters.

The avalanche occurred on the upper part of the slope.