As the typhoon season reaches its peak in Japan, local inhabitants of Saitama and Chiba were surprised on Monday afternoon by a freak tornado which injured over 60 people and wrecked over 100 buildings.
The tornado began in Koshigaya, Saitama Prefecture, injuring 63 people and wrecking buildings before going on a 14-km rampage into neighboring Chiba, local police said. It swept through houses and fields around 2 p.m., knocking down utility poles, peeling off roofs and sending debris into the air. According to local police one man’s skull was fractured by an object sent flying by the tornado. In Koshigaya, seven buildings were destroyed and another 100 severely damaged. About 4,000 households were also left without power by the twister.
Based on police data from the two prefectures, the tornado wreaked havoc along a 13.8-km stretch, touching down in Koshigaya before veering northeast toward the town of Matsubushi and heading to Noda, Chiba Prefecture. In Matsubushi, the roofs of 10 houses were ripped off but no injuries were reported. In Noda, however, the twister damaged 27 cars, the roofs of 68 houses and knocked out power to about 6,200 households.
The Japan Meteorological Agency reported that the tornadoes were likely caused by a thundercloud called a “supercell,” which has generated mega tornadoes in the United States and elsewhere in the past,
Meanwhile, the Agency also announced on Aug. 30 that in a response to an increase in severe weather events they had started a “special warning” (tokubetsu keiho) designation for natural disasters that are very likely to cause heavy damage. As Mr. Mitsuhiko Hatori, director general of the agency, said, a special warning means that a life or death situation is imminent. Once such a warning is issued, the general public and local governments must think that a life-threatening situation is approaching and take necessary action — that is, evacuate quickly to minimize the possibility of disaster-related casualties.
Special warnings will be issued for heavy rains, storms, high tides, high waves, heavy snow and blizzards. But the agency will continue to use the conventional terms “emergency earthquake early warning” (kinkyu jishin sokuho) for an earthquake whose intensity is six or higher on the Japanese scale of seven, “eruption warning” (funka keiho) for a volcanic eruption that requires evacuation and “major tsunami warning” (o-tsunami keiho) for a tsunami that is more than three meters high. The agency said that these conventional terms are on a par with special warnings.
In the case of heavy rains, a special warning will be issued for each municipality when a record heavy rain for the past 50 years is imminent. The agency has set a criterion for issuing a special heavy rain warning by studying past precipitation records, including precipitation for three hours periods and for 48 hour periods, in individual municipalities across the country.
From the rainy season to autumn, people watch for a special heavy rain warning, due to climate change localized heavy rains are occurring more frequently in Japan nowadays. In the past month, record heavy rains hit the Tohoku and Chugoku regions, causing casualties. If the new criteria are applied, these heavy rains have been strong enough to merit the issuance of special warnings. At that time, the agency called on local residents to “immediately take an action that protects your life.” But it turned out that the call came too late for some areas — after the peak of heavy rains passed. The agency now plans to improve the accuracy of its weather forecast so that future special warnings will be issued in a more timely manner.