Heavy snow turns Japanese roads into a winter carnival... of jam!

Heavy snow brought traffic chaos to much of northwest Japan on Friday, with hundreds of vehicles stuck on blocked highways.

"The government will do its utmost to rescue anyone who is stuck in their vehicle," the government's top spokesman, Chief Cabinet Secretary Katsunobu Kato, said at a regular briefing.

Self-Defense Force troops were delivering food, petrol and blankets, and helping clear snow, while fire service crews rescued some drivers, including at least three people who were taken to hospital, according to public broadcaster NHK.

As highway workers in hard-hit areas such as Niigata prefecture cleared snow several feet deep in places, the Meteorological Agency warned of heavier snow over the weekend along the Sea of Japan coast.

Some places are bracing for as much as 80 cm (32 inches) of snow amid a cold snap that has affected much of the country.

Extreme cold conditions are expected to persist in the country