Kazuyo Miyashita, 40, her two daughters Misa, 17, and Sayo, 14, and her son Daiki, 11, died at a hospital Saturday night of carbon-monoxide poisoning after their vehicle got buried in the snow, according to Kyodo news service.
Separately, Haruna Kitagawa, 23, froze to death after leaving her car, stuck in the snow. A 53-year-old man died Sunday after getting buried in the snow, although his 9-year-old daughter found with him was recovering, Kyodo said.
Also over the weekend, a 54-year-old man and a 76-year-old man were found collapsed in the snow in another part of Hokkaido, and both were confirmed dead, it said.
The storm caused two-meter-high (six-and-a-half-feet) drifts and was blamed for derailing a bullet train in Akita prefecture, south of Hokkaido, on Saturday afternoon. Kyodo said the passenger train was moving slowly because of the heavy snow on the tracks, and the derailment caused no injuries.