豪雨被害 的確な情報で早めの避難を

The Yomiuri Shimbun (Jul. 18, 2010)
In 'guerrilla rain' fight, the key weapon is data
豪雨被害　的確な情報で早めの避難を（7月17日付・読売社説）

Torrential rains caused by a seasonal rain front have brought death and destruction to the nation, mainly in western Japan.
　西日本を中心に、梅雨前線の影響による集中豪雨の被害が相次ぐ。

A number of people have been killed or are missing. The victims were crushed in their homes by mudslides or swept away by rain-swollen rivers.
　土砂崩れで倒壊した家屋の下敷きになったり、増水した河川に流されたりして、大勢の死者・行方不明者が出ている。

In the past month, there have been over 350 reported landslides. In Matsue, a mudslide on the slope behind a private house caused two huge rocks, each measuring four meters in diameter, to strike the building, killing two residents. In Yaotsucho, Gifu Prefecture, a mudslide crushed a private house, killing three residents.
　とりわけ土砂災害は、このひと月余りで３５０件を超えた。

　松江市では、住宅裏の斜面が崩れて、直径４メートルの岩２個が民家を直撃、２人が死亡した。岐阜県八百津町でも民家が押しつぶされ、住人が死亡した。

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Landslides must be studied

In recent years, experts have attributed large-scale mudslides to the so-called deep-seated landslide mechanism. Heavy rain soaks into cracks in the bedrock, which has been weakened over time, and when the bedrock collapses downhill, it takes a large volume of upper soil with it.
　近年、専門家からは、大規模な土砂崩れについて「深層崩壊」というメカニズムが指摘されている。長い間に風化した岩盤の亀裂に大雨がしみこみ、脆弱(ぜいじゃく)化した岩盤ごと大量の土砂が崩落する。

Unlike shallow landslides, which can be prevented to a certain degree through good forestry practices, there are no known measures to prevent the occurrence of deep-seated landslides. We consider it necessary to urgently study what steps could be taken.
　森林保全で一定の予防ができる表層崩壊と違い、発生を防ぐ手だては今のところないという。対応策の研究を急ぐ必要がある。

Meanwhile, the phenomenon of so-called guerrilla rain--sudden downpours into relatively narrow zones, mainly in urban areas--has attracted attention in recent years. Such rain is caused mainly by cumulonimbus clouds that form in a clash of warm and cold air. But some experts think the urban heat island phenomenon and global warming trends have a causal relationship to the sudden downpours.
　一方、都市部を中心に、狭い地域を突然襲う「ゲリラ豪雨」も近年の特徴だ。冷たい空気と暖かい空気がぶつかってできる積乱雲が主な原因だが、ヒートアイランド現象や地球温暖化との関係を指摘する専門家もいる。

Guerrilla rain is frightening in that it is difficult to predict and the damage it causes occurs all at once.
　襲来予測が難しく、被害が一気に発生するのが怖いところだ。

In the summer of 2008, five workers died in Tokyo after being washed away by a surge in sewer water while working underground. Also that summer, a swollen river killed five people, including primary school children, in Kobe.
一昨年夏には都内でマンホール内の水が急増して作業員５人が死亡。神戸市内でも川が増水して小学生ら５人が死亡した。

On July 5 this year, an intense rainfall of 107 millimeters per hour was recorded in Tokyo's Itabashi Ward.
東京・板橋では５日、１時間に１０７ミリという猛烈な雨が観測されている。

To prevent damage from heavy rain, it is essential to have highly accurate weather forecasts and to issue appropriate warnings. Such information must be adequately conveyed by local governments to residents in affected areas. It is imperative that those residents be advised to evacuate if necessary as soon as possible.
　豪雨被害の防止には、精度の高い気象予測と警報の発令、それを自治体が的確に住民に伝え、早めの避難を勧めることが大切だ。

The Land, Infrastructure, Transport and Tourism Ministry has started introducing advanced radar systems capable of accurately measuring the strength of precipitation mainly in major cities. Such radar can also be used to predict situations in wide areas affected by heavy rain. There also are private-sector services offering guerrilla rain forecasts on mobile phone sites.
　国土交通省は大都市を中心に、雨の強さが正確に計測できる高性能レーダーの導入を進めている。集中豪雨の広範な周辺状況まで観測できる。民間でも携帯電話サイトを使ったゲリラ豪雨の予報サービスが登場している。

Since late May, the Meteorological Agency has issued warnings and advisories on heavy rain and floods in a much more detailed manner as it increased the number of forecasting areas from 375 to 1,777 to correspond to each municipality.
　気象庁は５月末から、大雨や洪水などの警報・注意報を、従来の全国３７５地域から市町村単位（１７７７地域）に細分化して発表するようにした。

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Stay alert to stay safe

We urge each municipal government to effectively use such information to issue advisories and instructions for evacuations of local residents. It also is important that local governments regularly conduct disaster drills and establish systems to provide local residents with necessary information via community wireless services and other means in the event of an emergency.
　市町村には、これらの情報を住民避難の勧告や指示に、有効に生かしてもらいたい。日ごろから避難訓練を実施し、いざという時には防災無線などを使って必要な情報が確実に住民に届く体制作りをしておくことも重要だ。

As the rainy season winds down across the nation, summer vacations will soon start for schoolchildren. We are entering a holiday season during which people flock to beaches, mountains and rivers. People must not forget to take precautions against rain and flood disasters wherever they go.
　列島は南から順次、梅雨が明ける。子供たちの夏休みも始まる。海・山・川がにぎわうシーズンだ。どこへ行っても雨と水への警戒を怠らないようにしたい。

(From The Yomiuri Shimbun, July 17, 2010)
（2010年7月17日01時49分 読売新聞）