The temperature in Sapporo dropped to minus 7C on Monday night, with snow beginning early Tuesday.
By dawn on Wednesday there was 44cm of fresh powder snow on the ground – the deepest snow to cover Sapporo since 1953.
The ski resort of Niseko just south of Sapporo received 24cm on Tuesday. Significantly more is expected in the next two or three days.
Snow fell as far south as Shirakawa, halfway down Honshu, in Gifu Prefecture.