Tornado near Tokyo kills 1 and injures dozens

[frostfern]

I saw it being issued once when I was searching for tornado videos on Nico Douga, which is a Japanese video site. It was while the person was watching TV and the warning popped up. It said 竜巻警報 tatsumaki keihou, meaning "tornado warning." I couldn't find it mentioned as an official product on the JMA site anywhere, though.

On TV Japan, I just watched a 30-minute NHK documentary on the tornado called "Today's Close Up." They showed a radar animation of the storm that produced the tornado, a classic supercell with the flying eagle and a well-defined hook. They noted how this type of storm was rare in Japan, but common in America. They showed the 14-year old victim's house, which had been turned upside down, literally. The concrete foundation had toppled over with the house and was now facing up away from the ground. The question came up about how it was that the tornado could have done this, when it wasn't much stronger than some typhoons, which would never have done that. It was explained that with a typhoon you just have the horizontal motion, which the house can withstand, but with a tornado you have not just the horizontal motion, but also a very strong vertical motion that helps the horizontal winds topple the house. Before watching this, I had not understood that about vertical motion

The man they interviewed was Fumi'aki Kobayashi, a meteorologist who specializes in the study of tornadoes, and he surveyed the damage and did a really good job of explaining how supercells form, how tornadoes form, and what goes on inside them.

Another thing is unlike straight line winds, tornadoes carry debris along with them for long distances due to the circular motion and inward suction. The high concentration of debris gives the wind more power to take out the lower windows and doors and once those are gone the wind blows straight through the structure, lifting it due to the upward Bernoulli force. Also, with a typhoon people have time to board up windows and exterior doors.

[beneficii]

Another thing is unlike straight line winds, tornadoes carry debris along with them for long distances due to the circular motion and inward suction. The high concentration of debris gives the wind more power to take out the lower windows and doors and once those are gone the wind blows straight through the structure, lifting it due to the upward Bernoulli force. Also, with a typhoon people have time to board up windows and exterior doors.

Thanks. Kobayashi didn't go into that much detail, but he did mention the effect of the debris moving from one building to the next.

He also mentioned the intense drop in pressure, more than 100 hPa (same as 100 mb), as you move toward the center of the tornado and the constant changing of direction of winds, which gather in a small space as they try to cram into the center of circulation. He mentioned that the winds and debris continuing to hit the structure causes it to become deformed, possibly making it vulnerable to destruction as the winds continue to pound on the structure.

[beneficii]

thanks patrick05 really interesting stuff for sure !! thanks yeah let me know where i can watch that gotta look for it when i get home today.

It was on TV Japan, originally broadcast last Monday, I believe. I'm not sure if they're going to show it again, though. That's why I have it DVR'd and protected.

[beneficii]

OK, I used my cell phone and converted it to GIF. Not the greatest quality, but it'll do:

http://imgflip.com/i/3tut

This is taken from the Tsukuba radar as the tornado was moving through. The location of the supercell and tornado should be obvious from the radar presentation, as the supercell seemed to take on a classic shape. The radar goes through twice, with the second time closed up on where the tornado was occurring; here you can see the hook and flying eagle formation clearly.

Also, the tornado was upgraded from an F2 to an F3; Japan still uses the original Fujita scale.

[beneficii]

Here's a YouTube video of it. It's better quality:

[beneficii]

Here's a translation of what the narrator was saying:

This is the rain cloud, which was depicted on the radar at Tsukuba at the time of the tornado. What you can see as red is the cell that formed. Its size was at least 10 kilometers, so it's a giant cell. This tornado, which was just to its south, formed and brought great destruction.

This is the original Japanese:

当時、つくば市にあるレーダーが撮らえていた雨雲です。赤く見えるのが発達した積乱雲。大きさは10キロ以上巨大なものでした。この、すぐ南にある竜巻が発生し、大きな被害をもたらしていました。

[beneficii]

check this out:

http://photo.sankei.jp.msn.com/highlight/data/2012/05/06/13tsukuba/