“Unprecedented” Floods in Japan Bring Fatalities, Evacuation

More than 5,000 people are cut off by landslides as more heavy rain and floods are forecast in southwestern Japan on the island of Kyushu, where the death toll from torrential downpours has risen to 22.

About a quarter of a million are affected by evacuation orders.

The city of Aso, where most of the fatalities occurred, received more than a month’s rainfall over three days.

A video at the BBC site says that at one location a month’s rainfall fell in 12 hours, and quotes the Japan Meteorological Service saying that such rainfall was “unprecedented”, though the exact context is not reported.


  1. The rainfall is disasterous and really unprecedented in local perspective, but just that. In a broader regional perspective, heavy rain events in July in the Meiyu/Baiu frontal zone is not surprising. It is difficult to demonstrate that a systematic change in the occurrence of heavy rain events has happened, as presumably natural interdecadal variability is also large.

  2. The report from Japan Meteorological Agency is here, in Japanese.
    http://www.data.jma.go.jp/obd/stats/data/bosai/report/index.html .
    And a scientist whom I trust has a blog http://disaster-i.cocolog-nifty.com/blog/ , but he thinks his audience is Japanese-speaking people. It seems that we need to have translators in order to compile information from many parts of the world together, and I am sorry I cannot volunteer the Japanese part.

    It follows from the statement I made in the previous comment that the current Japanese event should not be used as a cause to mitigate anthropogenic climate change, even with the precautionary principle. (As many causes acts simultaneously, the precautionary principle may justify too many things.) It does demonstrate our vulnerability to such floods that will occur more frequently according our scientific (rather theoretical than empirical) reasoning.

    Perhaps ironically, information of extreme events (and disaster mitigation) drives us towards adaptation rather than mitigation of climate change.

  3. Thank you Masuda-san.

    I agree that we need more translation. It's among the numerous ambitions I have for the climate web, whether provided by P3 or otherwise. More about this to follow. Such translation would have great value compared to their cost, but it is nevertheless difficult to identify a reliable funding mechanism.

    Regarding the particular event, it is as always difficult to attribute an individual event. The question at hand is whether it is enough of an outlier to add to our litany of outliers to demonstrate whether climate change is already causing great harm. How to address this question objectively and fairly is very difficult but I would argue that it is very important - if large costs are accruing already this greatly shifts the optimal policy toward mitigation.

    For myself, I have been leaning to the affirmative since the Australian drought of '09, and this is why I think it is important to report extreme events on this site. But I do not wish to claim that the conclusion is beyond dispute, and so I do not think we should report ordinary extremes.

    Also, disasters which are to some extent the result of poor planning or execution of adaptation systems are also well within our purview here.

    But we do not want to call attention to "ordinary" disasters. An F3 tornado in May is not an issue for us to consider, even if it has tragic consequences. A few hundred tornados in a region in a week is another matter.

    So we do not have, across the language barrier and the feeble capacities for scientific nuance in the press, a clear indication of whether to consider this particular unfortunate event or otherwise, and I read your information as rather inconclusive or marginal on the key question. Is that correct?

  4. I think that's somewhat circular reasoning in your first comment, Kooiti. If natural variability has no limit, pretty much anything can be fit under that tent.

    And in your second comment these two statements seem directly contradictory:

    "the current Japanese event should not be used as a cause to mitigate anthropogenic climate change, even with the precautionary principle."

    "It does demonstrate our vulnerability to such floods that will occur more frequently according our scientific (rather theoretical than empirical) reasoning."

    With the added energy in the atmosphere, why should the presumption be that unprecedented event of this type are not enhanced by AGW? Why not make the other presumption?

  5. Note also the contemporaneous record drought in Korea, which is very close to Kyushu. The cause appears to be yet another blocking high, making the overall situation sound similar to what happened in Russia and Pakistan, albeit on a smaller scale.

  6. The phrase "unprecedented flood" happened to be newsworthy. It was used by the Japan Meteorological Agency as a part of their new format of warning, and, ironically because it was a brand new and no one had experienced before, it did not provoke the desired high level of awareness.

  7. The new term used by Japan Meteorological Agency should be translated to "unprecedented rainfall". I was careless when I interpreted as "unprecedented floods". The warning of JMA does imply high flood risk, but warning of floods at specific places is not the responsibility of the weather service. It belongs to local governments, or sometimes other branches (River Bureau, Forestry Agency etc.) of the national government. But the information people get from mass media mainly consists of the weather service, and it makes them frustration due to under-specification.

    There was a news talk show at NHK (something like BBC) on Wednesday 18th about the floods in Kyushu with a focus at the warning issued by JMA. Dr Motoyuki Ushiyama, whose blog I mentioned above, appeared as a guest speaker. The official transcript (in Japanese) is here: http://www.nhk.or.jp/gendai/kiroku/detail_3230.html

    As I mentioned above, the flood was locally unprecedented in the history of modern observation (somewhat longer than a century), but not surprising regionally (e.g. in the perspective of the whole Kyushu island).

    Incidentally, though one example never proves a trend, not this event but the F3-scale tornado event of around Tsukuba in May made me feel (subjectively) that our climate is really changing. The magnitude was certainly a minor one if happened in the central USA, but very rare regionally (in Japan, I mean, rather than just in Tsukuba), though I am not very sure because our history of quantitative evaluation of tornadoes is short. That event was discussed in NHK here. http://www.nhk.or.jp/gendai/kiroku/detail_3193.html

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