The seven—four men and three women—were climbing or skiing when the avalanche, an estimated 30 meters (98 feet) wide and 600 meters long, hit on a western slope of the 2,860-meter-high Mt. Masago, police said.
They were taken to hospital by helicopter but were confirmed dead, police said.
A local police officer said rescuers were continuing the search as it was not clear if there were any other people on the mountain at the time of the avalanche.