Eight people died amid heavy snowfall in Hokkaido over the weekend, including a woman and her three children trapped in their car, police reported.

Kazuyo Miyashita, 40, her son, Daiki, 11, and her two daughters, Misa, 17, and Sayo, 14, have died of carbon monoxide poisoning after their vehicle's exhaust pipe and windows were buried under snow Saturday in the town of Nakashibetsu, filling the car with toxic fumes, the police said.

A nearby resident made an emergency call at 7:10 p.m. Saturday, but it took police and rescue workers two hours to plow through more than 2-meter-high snowdrifts and reach the scene.

Also in Nakashibetsu, Haruna Kitagawa, 23, was found collapsed on farmland and was later pronounced dead at a hospital Sunday morning. The victim had apparently abandoned her snowbound car, which was found about 300 meters from the scene.

In a separate incident, Mikio Okada, 53, was pronounced dead Sunday after he and his 9-year-old daughter were buried in snow in a rural area of the town of Yubetsu. According to police, Okada was confirmed dead at a hospital but his daughter, Natsune, survived without serious injury.

The two went missing after leaving home Saturday afternoon to visit one of Okada's friends. Police and rescue workers said they discovered their truck that evening, but weren't able to locate the pair until Sunday morning.

Okada had called his friend via cellphone immediately after setting off, and reported that their vehicle had become stuck in heavy snow, according to the police.

Meanwhile, two other Hokkaido residents, aged 54 and 76, were found lying unconscious outdoors in the cities of Abashiri and Furano. The two men were pronounced dead later Sunday, the police said.