Caption: “Miyagi, Tochigi, Ibaraki: 4 Dead, 15 Missing; 12,000 households affected by flooding.” Screencap from ANN official YouTube Channel.

Last week Tokyo and the Kanto region endured days of torrential rain caused by Typhoon Etau. Bedroom communities and prefectures to the northeast of Tokyo were hit hard by massive, unexpected flooding.

At least 12,000 households were affected by the flooding that left at least four dead and at least fifteen people missing.

The sheer scale of the flooding was surprising, and was reminiscent of the devastation caused by the massive tsunami that struck northeastern Japan in March, 2011.

While Typhoon Etau affected a large geographic region northeast of Tokyo, one of the hardest-hit cities was Joso, Ibaraki Prefecture, about 60 kilometers northeast of central Tokyo.

Heavy rains breached and destroyed the Kinugawa River levee.

大規模な水害に見舞われた #鬼怒川 周辺の衛星写真を Google 災害情報マップ https://t.co/g3B8PVs2uN で公開しました。被災された皆さまの安全と一日も早い復旧を心から願っています。 pic.twitter.com/DW4484QzIG

— Google Japan (@googlejapan) September 12, 2015

Google Crisis Response Map showing [before-and-after] satellite image of large-scale flooding affecting #Kinugawa area: http://www.google.org/crisisresponse/japan We hope and pray from the bottom of our hearts that everyone remains safe and can start rebuilding their lives as soon as possible.

News reports also showed the scale of the flooding:

News networks provided non-stop live coverage of the calamity. Users shared some of the images on Twitter:

鬼怒川堤防が決壊した地区の生中継ずっと観てました！ 放送画面で私が確認した人達は自衛隊の活躍によって全員救助されたと思います！ 自衛隊もスピードと確実性を要求される中よく頑張った！ 他の地区の人も頼んだぞ！(º_º)ゞ敬礼 pic.twitter.com/IdShgLzu6v

— アルパパ@愛媛 (@EHIMEnoNOBU) September 10, 2015

Here's live coverage from where the levee broke on the Kinugawa [River]. Thanks to the JSDF (Japan Self-Defense Forces), everyone stranded on the rooftop was saved. The JSDF was really able to work quickly to save them once alerted of the situation. Hopefully people stranded in other flood-hit areas can be saved! They're in our prayers!

The operation to rescue a couple and their dogs was one of the most shared news items on Twitter:

これおじいちゃんが抱えてるの犬やんな 一切吠えずに救助されるのをじっと待ってるとか 正直涙出てきた #鬼怒川 #台風 pic.twitter.com/gRxxfTLDn0

— Tokky(ときふさ) (@tokkinaitospide) September 10, 2015

I couldn't stop watching television coverage of the eldery man being rescued holding his dog (who didn't bark or anything). When they were finally safe I started to cry.

Here's the entire rescue:

@tokkinaitospide おばあちゃんと犬一匹助かった おじいちゃんと犬もう一匹もう少しです #鬼怒川 #台風 pic.twitter.com/Oe4A6Smn2u

— Tokky(ときふさ) (@tokkinaitospide) September 10, 2015

The woman and her dog have been saved; next up is the man and the remaining dog.

Other viewers noticed that the television helicopter that captured images of the rescue may have been in the way:

救助されたは本当に良かったけれども、この家その10分後には流されてて、あと少し遅れてたらと思うとゾッとする。 とりあえず、救助活動妨害してたこのヘリの乗組員は雁首そろえて謝罪するべき。 #鬼怒川 #マスゴミ pic.twitter.com/1x3YcdlEYd

— 二郎丸 (@godon0318) September 10, 2015

While I think it's great that they were saved, just ten minutes later the whole house was washed away. I shuddered when I realized how close things were. Anyway, the crew of the helicopter here getting in the way of rescue operations should line up and publicly hang their heads in shame.

The Japan Self Defense Forces (JSDF, Japan's military) have been widely lauded for their efforts to quickly and efficiently help people affected by the flooding.

The JSDF themselves have been active on Twitter and in other media, promoting their rescue and recovery efforts.

関東地方から北日本にかけての大雨に係る災害派遣についての状況です。 茨城県では引き続き、孤立者の救助、ボートによる避難支援及び土嚢による水防活動等に係る活動を実施しております。 #災害派遣 #自衛隊 #茨城県 #大雨 #鬼怒川 pic.twitter.com/hllANUIzwU

— 陸上自衛隊 (@JGSDF_pr) September 12, 2015

Here is the situation from Kanto to northern Japan after we were deployed to assist following torrential rains. In Ibaraki our efforts continue, helping those stranded by the flooding, and deploying boats deliver people to safety.

A house that proved to be remarkably resilient to the flooding has become a meme on social media:

一夜が明けたヘーベルハウスの様子 #鬼怒川　#堤防決壊 pic.twitter.com/biDPcStqmS

— ゆる系速報・ぽん太くん (@JPNG5) September 10, 2015

The Hebel House survived a night of flooding.

Hebel House is a brand of prefabricated housing in Japan. Prefabricated homes are fairly common in suburban Japan; components are manufactured in a factory and then shipped to a building site to be assembled by contractors.

Online news site Livedoor reported on the social media phenomenon surrounding the Hebel House. According to Livedoor, one commenter on the internet said:

「さすがへーベルハウス！」
「家建てる時はヘーベルハウスにしたい」

Of course Hebel House would survive the flood. When I build a house, I'm going with them!

Climate Change Means Changing Typhoon Patterns in Japan

Traditionally, typhoons move from west to east across the main Japanese island of Honshu, and some of their power is blocked by mountains bordering Tokyo's western outskirts.

Traditionally, typhoons move from west to east across the main Japanese island of Honshu, and some of their power is blocked by mountains bordering Tokyo's western outskirts. Image remixed by Nevin Thompson, from Wikipedia.

In recent years changes in jet stream patterns due to climate change have also changed typhoon landfall patterns in the Tokyo area.

Typhoons now typically arrive from the south and the open Pacific Ocean. With no mountain ranges to disrupt the power of the typhoon weather front, hot, humid, and intensely wet air flows northward over Tokyo and the flat Kanto Plain before being blocked by the wall of mountains that ring Tokyo to the north.

Because of climate change and changes to the jet stream, intensely wet weather patterns converge on Tokyo and the Kanto Plain directly from the south and the open Pacific. Image remixed by Nevin Thompson, from Wikipedia.

As a result, typhoons, which have become larger and more powerful in recent years, tend to cause more serious flooding than in past decades.

Last week's typhoon was a disaster for many, but also a learning opportunity for some. A Twitter user noted that someone on 2ch (“ni-chan”), Japan's answer to Reddit and 4chan, had carefully documented every variety of helicopter shown on television during the disaster recovery efforts.

2chで拾った誰かの労作だけど、今回常総水害に出動したヘリの画像。 pic.twitter.com/PyVflfODQw

— sf324929 (@sf324929) September 12, 2015

This was compiled by somebody on 2ch, but here are all the helicopters that helped out in the flooding at Joso, Ibaraki.