The weather agency confirmed that the windblast that struck Tsukuba, Ibaraki Prefecture, was a tornado of the fourth-highest ''F2'' level on the so-called Fujita scale for tornado intensity comprising six levels. An F2 tornado tears roofs from houses, uproots trees, blows cars off roads and derails trains with an average wind speed of 50-69 meters per 7 seconds.
Tornado left damage over 15-km area in Ibaraki Pref
A tornado that ripped through Ibaraki Prefecture in eastern Japan on Sunday, killing a teenage boy and injuring dozens of people, is believed to have left damage over a 15-kilometer swath about 500 meters wide, Japan Meteorological Agency said Monday.
The tornado and gusts in prefectures north of Tokyo including Ibaraki and Gunma have left 48 injured and caused damage to some 890 houses and buildings, according to fire department officials.