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Monday, 23 May 2011

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The lesson is "don't live in the heartland". (only earthquakes here in California)

We've had our share of disasters here in Australia this year, but I was truly horrified by the pictures on the news this morning, that tornado damage looked the the true apocalypse.
Everyone here really feels for anyone who lived in Joplin. Let's pray more survivors are dug out today.

I suppose its appropriate to comment on the photography, as opposed to the disaster.

Those photos communicate something that only genuine photojournalism can convey.

Facebook pages taken with iPhones or video footage give you part of the story.

But those photos really hit you in the gut.

Scary and sad. I've been more interested and concerned about these storms since moving south into the lower end of tornado ally. Nowhere else in the world comes close to the number of twisters produced in the USA between the Appalachians and the Rockies. (Florida gets their share too)

Folks here in the Austin area still talk about the 1997 F5 tornado that hit nearby Jarrell Texas. It was a 3/4 mile wide monster that formed under rare dry conditions. Filled with dry dirt it was a proverbial 200 MPH+ sanding drum that ground down everything in it's path.

I pray for the victims and hope to hell I never get to witness devastaion like this.

That's awful.

But I've always wondered... The worst wreckage in the photos consists mainly of planks. Why don't people in the tornado alley build houses of something sturdier?

Okay, stone is not readily available and probably would be prohibitively expensive, but bricks or cinder blocks certainly are? It's certainly not the 19th century when plank houses were all they could build in the prairie.

How fragile we are, and everything we call home. Good luck and my best wishes, all you people in Joplin.

Roger B.

"Why don't people in the tornado alley build houses of something sturdier?"

Erlik,
Three basic reasons. First, would you be prepared to pay 1.5X to 5X for your house? Most people don't have the cash, and don't have the option of custom-building houses--they have to choose from the available housing stock, i.e. houses that already exist. I doubt a bank would give you a mortgage for investing in a tornado-proof house--it would not be recoverable on resale. So you'd need to have the cash. Even most well-off people don't.

Second, it's very difficult to build a truly tornado-proof house. Almost nothing can take a direct hit from an EF5 without significant damage. They're just too strong.

Third, only a minuscule percentage of houses get directly hit by tornadoes. There were more than 1500 tornadoes in the U.S. in 2010, but there have been only 85 cases in the past 140 years where tornadoes have hit downtown areas like the Joplin tornado did. Even with the country built up like it appears to be, there is still greatly more land area with no houses than there is land area covered by buildings. 75% of tornadoes are "weak" tornadoes that don't do extensive property damage (no solace to the 1/3rd of tornado fatalities they cause). A really big tornado can destroy large numbers of homes (there are no statistics that I can find) but it's still only a tiny percentage of all the homes there are. Even if your town or area takes a hit by a strong tornado, there's still really good odds that your home won't get hit. (Again, small consolation to those who are.) A town near me, Eagle, was hit by a strong tornado in 2010. Twenty houses were destroyed. But there are 605 housing units in Eagle. And it's rare to have a twister hit directly in a village or town like Eagle.

So, do you spend the ~3X to try to make your home tornado-proof when the chances are very small it will ever be hit? Given that if it IS hit it might not survive anyway?

The saving grace of tornadoes is that they don't reach below grade. This is one reason why a large percentage of homes in the Midwest have basements (I doubt there's a house on my street without one)--and why so many people do survive, even in the houses you see in pictures that are obliterated above ground level.

Mike

Thanks Mike.

Having seen the appalling after-effects of these recent tornadoes, and also the spectacular but terrifying images made by 'storm chasers', I can't help but feel that, whatever God designed the Mid-West for, it wasn't people.

Interesting thoughts on tornadoes Mike.

I worked for a few years for a big US company that has both defence and civil science programmes. The company won a biggish research contract from the US Government to look at all possible ways in which tornado damage could be reduced as part of a system of systems (ie prevent tornadoes, maximise warning time, cause tornadoes in safe areas, divert tornadoes, stop tornadoes, minimise damage). Some of the ideas for stopping or diverting tornadoes appeared to me to be "weird science", but they included things like warming descending cold air with microwave beams, seeding clouds to release moisture and lose heat, and inducing lightning in certain areas to reduce electrical potential.

I left the company for another job well before the research concluded, but at least some agency of the US Government is looking at the problem.

Meanwhile, I have respect for midwesterners who live with this figurative "Sword of Damocles" over their heads, and a great deal of sympathy for the people of Joplin.

The destruction wrought by these storms is simply unimaginable, yet we never hear of this sort of storm or destruction in other parts of the world. Are the US Midwest/Southeast and now Mid-Atlantic regions unique in some way that causes these storms? Doesn't seem possible but when is the last time we heard of a tornado in Italy or Germany?

I cannot even imagine. Heartbreaking to see, but hopeful that so many did survive that.

Ed,
The U.S. has four times as many tornadoes as Europe, but the Netherlands has the most tornadoes per unit of area, and the U.K. the most of any country. It's just that most of the Netherlands' and the U.K.'s events are very weak and don't do much damage, so you don't hear about them. (Source: Wikipedia > Tornado > Climatology.)

The U.S. averages about 1200 tornadoes annually. About 300 of those are "strong" tornadoes (the kind that can destroy buildings and toss cars and trucks around).

Mike

So, do you spend the ~3X to try to make your home tornado-proof when the chances are very small it will ever be hit? Given that if it IS hit it might not survive anyway?

Well, that's the way people build quake-resistant buildings in other countries. (Not really really resistant, but you know what I mean.) You cannot prevent damage from the strongest quakes, but you can lessen or even fully avoid damage from the weaker ones. For instance, there's a law how buildings have to be built here - stuff like apartment buildings and so on - in order to make them safer from quakes.

I'd say the main reason is banks clinging to their money argument, which I think is specious. But I don't see your government curbing them.

Picture 24 in the first link provided (the one of the couple finding their dog), is amazing; it perfectly captures a moment of true joy and relief in the midst of something truly terrible.

Excuse me, I've got something in my eye here...

Yeah, no place is really free of natural disasters.

I'll take tornadoes over earthquakes any day, though. You generally get warning of tornadoes, and the basement (or inside rooms in big steel-frame structures) are pretty safe so there's someplace to go when you get the warning. And they don't devastate an entire region -- so if you ARE buried in the rubble in your basement, emergency services will be able to get to you in time to dig you out most of the time (they're not totally overwhelmed).

Given the New Madrid fault, I think maybe we'd have to build our tornado-proof houses to fairly high standards of earthquake survivability as well (unreinforced masonry is REALLY bad in a quake).

I once had the building of tornado-proof buildings explained to me like this:

These are rare events, and since there is some warning, most of the time people can get to a basement and will be OK. So then it comes down to the cost of insuring the flimsy building, as opposed to building a strong one, and this is much cheaper. If you expect less than one per century, then insurance should add <1% to the cost. While as Mike said, building strong could increase it several times.

(And no, erlik, it's not greed. Steel wood and labour put into stronger houses are real costs, they translate into less other stuff people also want: living space, cars, holidays, hospitals. And cameras!)

The difference with earthquakes is that there is no time to leave the building before it collapses, so you have to make it strong. (Perhaps this goes for tall buildings in tornadoland too?) And also they tend to affect a large area, rather than just a narrow strip. You seldom have to walk far from a tornado-destroyed house to find shelter, or medicine. This second difference applies to hurricanes too: you need to worry about the whole island being hit at once.

The guy who was explaining this was testing buildings for hurricane-prone islands. One of the tests involved a special cannon for shooting coconuts at the windows, and they had to bounce! I don't know exactly what speeds they designed for, but of course strong tornadoes come with higher winds than strong hurricanes.

That said, of course what happened in Joplin is a tragedy, and the pictures are certainly horrifying!

Two co-workers were staying at a hotel in Joplin on the Friday before the storm working in the region on a video project. They called to say they didn't know if their flights back to DC would go that day because the sky was ominous--"it looks like night at 8:30AM" was the description I received. In the end, they were able to travel out. Lucky for them.

The way I saw it explained (in "Frontier", by Tim Flannery, I think) was that the two huge north-south mountain ranges you guys have on each side of the North American continent funnel warm and cold air masses towards each other, so when they meet you get eddies. Sometimes really big eddies.

Sometimes I appreciate living in the UK. Yes it rains now and again, but it's easy to forget how much more capricious nature is in other parts of the world and how helpless we still are to counter it.

Seems like the weather systems in the US are building up to deliver more misery in the next few weeks. It's hard to imagine how stressful it must be living with this constant threat.

My heart goes out to all those affected over the last few weeks and those worrying about where and when the next one will strike.

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