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Bizarre weather signals threat of monster typhoons

Aberrant weather patterns have made for a strange rainy season so far this year, reports Friday (7/22). For one thing, the rain front came to a halt over Niigata Prefecture on the Sea of Japan, inundating the prefecture while Shikoku, on the opposite side of the archipelago, saw nary a drop. And Tokyo got hit by a June day with record-setting high temperatures.

It remains to be seen if the record-breaking number of typhoons that made direct landings on the Japanese archipelago in 2004 --- 10 of them --- will be exceeded. But just about everyone agrees that the seasonal weather patterns aren't what they used to be.

"This is just the beginning of real changes in weather patterns on a worldwide scale due to global warming," says Koji Murayama, a meteorologist who works for the Japan Meteorological Business Support Center. "Once it begins, the common wisdom in our field is that the frequency of irregular phenomena will increase and their scale will become increasingly greater."

Murayama is especially concerned that a Class-5 typhoon will hit Japan this summer.

"A rise in ocean temperatures caused by global warming caused all those typhoons to be generated," he says. "Just a minor change in atmospheric pressure is enough to generate them. Since ocean temperatures this year are even higher than they were in 2004, I won't be surprised to see a large number of typhoons. They are also becoming more powerful. It's possible that Japan will be hit be not one, but several big ones."

Japan's Meteorological Agency defines the largest class of typhoon as having winds in excess of 54 meters per second, or with a radius of 800 kilometers or greater. The famous killer typhoon that struck Ise Bay (centered around Mie and Aichi Prefectures) in 1959 had winds measuring 60 meters per second and boasted a radius of 900 kilometers.

Hypothetically, if a typhoon in the class of the monster that flattened Ise Bay in 1959 were to strike the capital, it would be capable of flooding --- get this --- 41 percent of Tokyo's 23 central wards, inundating a total area of 265 square kilometers, including major parts of Koto, Sumida, Taito and Arakawa wards. A similar catastrophe in Osaka would inundate the low-lying parts of Konohana, Minato, Taisho and Suminoue wards.

"Because urban streets are paved, the excess water would be channeled underground," says Toru Nakamura, an executive at the National Institute for Land and Infrastructure Management. "The small rivers and streams are not well protected from overflowing, and there's a strong risk that the subways would become inundated in a very short time. If that happens, people might be find themselves caught in flash floods and unable to flee in time."

In the event of a monster typhoon, the most sensible precaution would be to head for the safety of the hills at least a day before it arrives.

"Above all else you need to have the right understanding of the data at hand," advises the aforementioned Murayama. "Since typhoon information is issued 24 hours beforehand and data on torrential rains at least several hours in advance, you can take measures to be sure you're out of harm's way."