TOKYO  - At least six people died in a spate of snow-related incidents as blizzards swept across the northern Japanese island of Hokkaido over the weekend, police and news reports said. A 40-year-old woman and her three children were found dead in a car buried under snow in the town of Nakashibetsu, eastern Hokkaido. They are believed to have died of carbon monoxide poisoning as the car’s exhaust pipe and was blocked by snow and the windows were up, Kyodo News said.