An avalanche struck a Japanese ski resort midmorning on Monday, overwhelming a student mountaineering exercise and leaving at least eight people with no vital signs, according to local authorities. Some 40 other students and teachers were injured in the avalanche, which hit the area in Tochigi Prefecture, nearly 100 miles north of Tokyo.As the BBC notes, Japanese rescue officials typically will not pronounce victims dead until they receive confirmation from doctors at a hospital.CNN, citing local police, reports that 62 people — mostly students — had descended on the small Nasu Onsen Family Ski Area for a three-day training program that attracted participants from seven high schools. Though the resort had recently closed for the skiing season, it had made some areas and facilities available specifically for the exercise.Hints of trouble arose Sunday, when the Tochigi branch of the Japanese weather service issued an avalanche warning due to worsening conditions, according to The New York Times. Roughly a foot of snow fell between midnight and about 9:20 a.m. local time, when The Guardian says the avalanche struck.This spring snowfall, which followed a spate of relatively warm weather, made for a particularly dangerous combination."We had heavy snow that condensed [with the warmer weather], and then once you have somebody on top of that, that creates a trigger," Robert Speta, a meteorologist for Japanese broadcaster NHK World, tells the Guardian. "These are all a recipe for avalanche creation."Still, teachers had experience with this trip, particularly at this time of year. And they believed they had made the proper adjustments to ensure students' safety, scrapping their original plans to scale Mount Chausu and instead turning to practice on lower, safer slopes, reports the Times."This (outing) is an annual event and we never had a major accident before," one of the teachers told Jiji Press, according to Al Jazeera. "I am really shocked.""Suddenly everything turned white," a male student who survived the disaster told NHK, the Times reports. "The teacher at the front yelled, 'Get down,' so we dropped down and got covered in snow. Then those of us who could move helped dig out people who were buried."Dozens of troops from Japan's Self Defense Forces were enlisted for the rescue efforts, which lasted hours amid continued snowstorms. The AP reports that two of the survivors remain in serious condition. Copyright 2017 NPR. To see more, visit http://www.npr.org/.