Nearly 50 students and instructors were caught by the morning avalanche in the town of Nasu in Tochigi prefecture, about 190 kilometers (120 miles) from the Japanese capital.
Police confirmed the death of the eight people late Monday, the prefecture said. Forty other people were injured, including two who were in serious condition, a prefecture report said.
Japanese media said the students were on the last day of a three-day training program for members of mountaineering clubs from seven schools in the area. They had earlier reported that all eight fatalities were students.
Heavy snow had fallen overnight, so a planned climb was canceled and instead students were practicing moving through heavy snow as mountain survival training, public broadcaster NHK said.
One unidentified student told NHK by telephone that there was a strong wind and he could see a white mass heading toward him. An instructor said to get down, and then everyone was engulfed, he said.
Tochigi prefecture said 40 students and eight instructors were on the slope. Fourteen others in the group did not go out Monday. The ski season had ended at the resort.