The Japan Meteorological Agency says a tornado that swept through a swath of Shizuoka Prefecture, central Japan, last Friday is likely to have been one of the strongest ever recorded in the country.The agency classified a strong gust of wind that hit areas stretching from the city of Makinohara to the town of Yoshida amid an approaching tropical storm as a tornado, after inspecting the extent of damage it left.The officials rated the intensity of the tornado as a three on the Japanese Enhanced Fujita Scale of zero to five.Japan has had 13 level-three tornados since record-keeping began in 1961, but the country has never experienced tornadoes at level four or higher.The officials said it is highly likely that a strong gust that hit the city of Kakegawa in Shizuoka was also a tornado. They rated it as a two on the JEF Scale.The agency said when people see cumulonimbus clouds developing, they should move to a safe place, like inside a sturdy building or a spot away from the window. It said such conditions could lead to a tornado forming in nearby areas.