Wind Speed of Tornado to Make a Road Damage
Minoru Noda and Fumiaki Nagao
*The University of Tokushima, 2-1 Minami-Josanjima, Tokushima 770-8506, Japan
Three tornadoes almost simultaneously hit the northern Kanto region north of Tokyo, Japan, on May 6, 2012. One peeled away and scattered asphalt 4 m wide, 30mlong and 50mmthick from roads in Tochigi prefecture. According to the Japan Meteorological Agency, the F scale of this tornado was between F1 and F2. A few F1-F2 tornadoes occur in Japan each year, but the scale of road damage following an F1-F2 tornado has not been previously observed. To determine the wind speed behind this road damage, a new approach was adopted focusing on the speed of flying debris and the pressure drop. The resulting determined a wind speed of approximately 100 m/s.
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