Numbers alone can be hard to visualize, but this makes things terrifyingly easy to understand.
How tall is a wave?
If you’re an avid surfer or sailor, you’ve probably got a pretty solid image of the height of a typical wave. But if your personal or professional interests lie outside those fields, odds are your grasp of the concept is a little less distinct, especially if asked to put it in numeric terms.
Still, most of us know that 16.7 meters (54.8 feet) is a really big wave. But…just how big?
I didn’t pick that number out of thin air, by the way. According to Yahoo! Japan, that’s the highest observed height of the March 11, 2011 tsunami in Iwate’s Prefecture’s Ofunato City. Roughly 3,500 homes, more than a fifth of all residences in the city, were destroyed in the tsunami, which also claimed the lives of more than 300 of its citizens.
So again, just how high is a 16.7-meter wave? As high as the red line on this skyscraper.
Yahoo!の壁面広告 pic.twitter.com/qynnloiDtZ
— MAEDA Takahiro (@maesan) March 5, 2017
That’s the Sony Building in downtown Tokyo’s Ginza district, where until March 12, Yahoo! Japan will be displaying the following message.
Every year, when 3-11 comes, we look back on what happened on that day. Six years have already passed since the Great East Japan Earthquake. We tell ourselves that disasters won’t happen again. But someday, a another disaster will probably, no, definitely occur.
On 3-11, in Iwate Prefecture’s Ofunato City, the maximum height at which the tsunami was observed was 16.7 meters. If the tsunami had happened here, in the middle of Ginza, it would be exactly this [the red section’s] height.
It’s higher than one would imagine. But just by knowing how high it is, the actions we take can change. We can make preparations here and now. We can receive the understanding and knowledge through our memories of the victims.
We won’t forget what happened that day. Yahoo believes that this is the most important part of disaster preparedness.
銀座のソニービルに、6年前の大津波の高さを体感できる赤い表示がありました。ヤフーの防災広告。ぞっとします。 pic.twitter.com/8OkdkhBD8q
— 矢崎 雅俊 (@yasaki_m) March 6, 2017
Making things even more chilling is that while Yahoo! Japan lists the tsunami’s height at 16.7 meters, Japan’s Kyodo News reportedly estimated the wave reached a height of 23.6 meters in Ofunato, which would move the mark even closer to the top of the 31-meter Sony Building.
https://twitter.com/sho_lab/status/838697288348270592Yahoo! Japan’s message makes no mention of or appeal to its services, and instead serves strictly as a somber reminder of how fragile life can be, and of the importance of being prepared for the worst even as we appreciate the times when circumstances allow us to enjoy the best.
Source: IT Media, Kyodo News via Wayback Machine, NPR, Twitter/@sho_lab

If the 2011 tsunami hit Tokyo’s Shibuya Scramble Crossing, this is how high it would’ve been
We visit a tsunami-ravaged region almost a decade after the Great East Japan Earthquake
Great East Japan Earthquake: Commemorate eight years and donate with a search on Yahoo! Japan
Simulation and helpful illustrations show the terrifying power of a one-meter tsunami 【Video】
Moving video commemorates anniversary of the 2011 Tohoku earthquake and tsunami in Japan
Nine great places to see spring flowers in Japan, as chosen by travelers (with almost no sakura)
Pizza Hut Japan teams up with creator of one of the country’s best kinds of ramen for ramen pizza
Japan has a cute Pokémon menu you probably don’t know about yet
Is this Tokyo government office still one of the best places in the city for a curry rice lunch?
Japan’s cherry blossom season predicted to start earlier than we’d thought, especially in Tokyo
Pikachu and Eevee become handmade Lladró porcelain sculptures to celebrate Pokémon’s 30th birthday
Which convenience store onigiri rice balls are the most popular? Survey reveals surprising results
Japan super budget dining – What’s the best way to spend 1,000 yen at 7-Eleven?
Studio Ghibli now sells Ursula’s backpack from Kiki’s Delivery Service at its anime shop in Japan
One Piece creator has hidden secret of anime treasure’s identity in chest at bottom of real-world ocean
Starbucks Japan unveils new sakura cherry blossom collection for hanami season 2026
Japanese government planning higher ticket prices for foreign tourists at Tokyo National Museum
Is Tokyo Station’s startlingly expensive wagyu bento boxed lunch worth its high price?[Taste test]
Starbucks Japan releases a new Cream Puff Frappuccino for a limited time
Silicone testicle covers banned from Japanese sauna following cups being left behind and on shelves
Live-action One Piece’s Luffy teaches Sesame Street’s Elmo a Japanese word for friendship[Video]
Mister Donut unveils new sakura doughnuts for cherry blossom season 2026
Japan’s newest Shinkansen has no seats…or passengers [Video]
Starbucks Japan releases new sakura goods and drinkware for cherry blossom season 2026
Foreigners accounting for over 80 percent of off-course skiers needing rescue in Japan’s Hokkaido
Super-salty pizza sends six kids to the hospital in Japan, linguistics blamed
Starbucks Japan unveils new sakura Frappuccino for cherry blossom season 2026
Foreign tourists in Japan will get free Shinkansen tickets to promote regional tourism
The 10 most annoying things foreign tourists do on Japanese trains, according to locals
Take a trip to Japan’s Dododo Land, the most irritating place on Earth
Naruto and Converse team up for new line of shinobi sneakers[Photos]
Survey asks foreign tourists what bothered them in Japan, more than half gave same answer
Japan’s human washing machines will go on sale to general public, demos to be held in Tokyo
Starbucks Japan releases new drinkware and goods for Valentine’s Day
We deeply regret going into this tunnel on our walk in the mountains of Japan
Studio Ghibli releases Kodama forest spirits from Princess Mononoke to light up your home
Major Japanese hotel chain says reservations via overseas booking sites may not be valid
Put sesame oil in your coffee? Japanese maker says it’s the best way to start your day【Taste test】
No more using real katana for tourism activities, Japan’s National Police Agency says
Great East Japan Earthquake memorial service broadcast in Shinjuku after years-long absence
Town destroyed by 2011 earthquake and tsunami creates anime based on stories of residents
You can help survivors of Japan’s 3.11 earthquake/tsunami in seconds with a quick Yahoo! search
Eva tie-wearing Japanese minister resigns after saying “it’s a good thing the tsunami hit Tohoku”
Japanese politicians propose officially designating March 11 as Great East Japan Disaster Day
Tohoku tsunami survivor’s $12K camera: heart-felt gift or PR stunt?
Seven years after earthquake, Fukushima teen says March 11 is an “ordinary day” in the prefecture
Annual Tokyo memorial for March 11 tsunami comes with a heartwarming musical surprise【Video】
Tsunami Survivors Share Their Stories: Resurrecting Otsuchi, Japan
Visiting the hotel half-destroyed by the 3-11 tsunami is a powerful reminder of what was lost
Tokyo Electric Power Company airs first commercial since Fukushima disaster, creates new mascot
Return to Fukushima: Decontaminated town reopens to residents, but is anybody living there?