Mike Smith of meteorological musings writes:
Brown Gashes on an Otherwise Green Earth
You’ll want to click to enlarge this image.
This from the AQUA earth-monitoring satellite. These tornadoes were so large they left visible brown gashes on the Alabama countryside. To help you find the gashes, storm chaser Aaron Kennedy put yellow lines parallel to the tornado’s tracks. I have added the arrows. The city of Tuscaloosa is between the “a” and my first arrow. The path across Birmingham was largely covered by clouds when the satellite passed over.
Mike also poses an important question.
I’m changing planes at O’Hare at the moment and just saw that the death toll is up to 250 per The Wall Street Journal and 272 per CNN. It is difficult to write this due to the shock that so many were killed when the forecasts and warnings were so good. That dichotomy is the question of the day.
Read his answer here
Ralph ,trees in the US are much hardier than thier UK counterparts. The fujita Scale refers to american trees that typicaly withstand up to an f-2. You have to refer to your wiki links you sent. The maximimum wind gusts were only 70 knots barely an F-1 while wiping out practically the whole english forest. The English learned long ago not to use their inferior trees for building as they would have to rebuild often.
As to the quality of the English anemometers you said it best, “gave up and died at 70”
See link to illustrate my point.
http://www.google.com/imgres?imgurl=http://www.kids-pages.com/folders/stories/The_Three_Little_Pigs/Three-Little-Pigs4.jpg&imgrefurl=http://www.kids-pages.com/folders/stories/The_Three_Little_Pigs/page4.htm&usg=__jbk1-mUxMJXkuvEA-M0HVkITeJE=&h=403&w=513&sz=46&hl=en&start=12&zoom=1&tbnid=UHsaj-8cFPewHM:&tbnh=137&tbnw=166&ei=SSi8TcLeD4fagQfC_-TABQ&prev=/search%3Fq%3Dthree%2Blittle%2Bpigs%26hl%3Den%26sa%3DX%26biw%3D1276%26bih%3D600%26tbm%3Disch&itbs=1&iact=rc&dur=265&page=2&ndsp=22&ved=1t:429,r:2,s:12&tx=71&ty=66
[When posting links, please give a few words of explanation. ~dbs, mod.]
We’re at the point where we are “talking past each other”; we HAVE done the enginneering, it’s the CONSTRUCTION of, the IMPLEMENTATION of those things that need doing (you didn’t read the PBAT/FEMA report I linked to above did you? I can only take SO much from thick-headed know-it-alls before I snap.)
Good day sir.
.
Mr. Moderator,
I am having trouble inserting links, I went to the test page (link at the top of this page) and tried to test my link language ? but found no place.. like this leave a reply box . Thank you in advance for your help on this matter.
Sincerly Cheapsmack
[Reply: Just cut the link from the address bar, and paste it in the comment box with a space before and after the link, and it will become active. ~dbs, mod.]
Ralph that is a wonderfull post I know you are tounge in cheek , but I really like the part where you have use trees as a proxy for wind speed .
>>cheapsmack says: April 30, 2011 at 8:12 am
>>The English learned long ago not to use their inferior trees for building
>>as they would have to rebuild often.
I think you should learn how to use the /sarc tag. There is not much that comes in hardier and stronger than the English oak, the tree that built Elizabethan England. And these were 300 year old trees that were felled in the 1987 hurricane, which demonstrates that this was a once in several centuries event.
>>Ralph that is a wonderfull post I know you are tounge in cheek ,
>>but I really like the part where you have use trees as a proxy for
>>wind speed .
Again, where is your /sarc tag. How do you think they estimate tornado wind speeds, for the many occasions when there was no doppler radar to measure them?
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Interesting idea – a Facebook page to track and reunite documents found downwind.
http://www.facebook.com/pages/Pictures-and-Documents-found-after-the-April-27-2011-Tornadoes/162443980482277
Ralph i found the wind load design requirement in the building code for england they vary some by height but are around 25-30 meters per second that would be around 50 miles per hour. Here is US wind load speed http://brobinsoncorporation.com/images/FloridaWindMap_MedRes.JPG
here is englands
http://www.sbsa.gov.uk/pdfs/windloadingtraditionaldwellings.pdf
where i live code is from 110 mph to 130 wind load design
Ralph says:
And these were 300 year old trees that were felled in the 1987 hurricane, which demonstrates that this was a once in several centuries event.
======================
“Once in a several centuries even for you”, maybe, not for us.
We have them all the time….as demonstrated in tornadoes and hurricanes every year.
You don’t!
And even EF3 tornados are not that common….nor are they that widespread.
NOR WAS THAT EVENT IN 1987 WAS NOT A HURRICANE.
Hurricanes are warm core systems and tropical in origin. So….stop calling that once in a 300 year event in the UK….a hurricane.
It was not.
Extratropical cyclones or not, the UK just does not have the volume of extreme severe weather that the USA does.
Absolutely not.
Your argument here is a complete red herring and you have no idea or concept about which you are talking.
Chris
Norfolk, VA, USA
Ralph says:
And these were 300 year old trees that were felled in the 1987 hurricane…
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Cite your evidence the tree trees felled were 300 years old…
You are hijacking this thread as you obviously have never been exposed to…or even remotely understand….instantaneous tornado damage.
Here is what it looks like in action:
Chris
Norfolk, VA, USA
Hi,
I’m from the Bahamas and during hurricanes, we have waterspouts that mount land as EF5 tornadoes during hurricanes. They aren’t reported as we attribute most damage to straight line winds and storm surges.
Reinforced concrete specifications are different int he US than in the West Indies, I think, correct me if I’m wrong.
After Hurricane Andrew, foundations are poured about eight feet(min depth) deep to accommodate connections to ground water wells. The above ground foundation is about 6 feet above sea level. Also, the outer walls are now required to be two cinder blocks thick with steel beams running through the blocks. Cement is poured through. This is a nightmare for cooling sometimes but it works. The two story buildings do the best because the second story’s floor is also concrete and steel beams. We do this to avoid the noise pollution you normally hear between floors of buildings. We have lost “many a roof” as we say but the strongest structures, those built during the colonial period have survived storm surges, straight line winds in excess of 200mph, and tornadoes. Hurricanes are dangerous in themselves but add violent tornadoes and spin-ups to the recipe and you have a very dangerous situation. Nothing can compare to a storm cellar, but I do believe that to save as much of the structure as possible, returning to some of the old construction techniques even though it may cost more, will help.
Oh yeah, you have something in the US that we don’t have in the Bahamas… Doppler radar systems that will warn you ASAP of any suspected rotation. We just listen for the train.
Golden says:
April 30, 2011 at 10:41 pm
Hi,
I’m from the Bahamas and during hurricanes, we have waterspouts that mount land as EF5 tornadoes during hurricanes. They aren’t reported as we attribute most damage to straight line winds and storm surges.
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No you don’t….and no they don’t.
The EF5 is the most violent atmospheric beast on the planet, and they do not even come close to the Bahamas….ever.
They are a continental phenomenon…and most specifically largely within the USA part of the North American Continent….and are caused by extreme differences in air mass, humidity, and wind shear
You do not have waterspouts that mount land with wind speeds in excess of 260 MPH.
Nor do you have straight line winds in excess of 260 MPH nor anything close.
You do not have extreme vorticity in 260 MPH plus winds that in a matter of 30 seconds, can suck the topsoil off the ground, and the pavement, too.
The closest phenomena like that in a hurricane, was the one that tore through the Florida Keys in 1935, but still even there, is not even close at those velocities reached in an EF5.
Storm surge is a completely different animal, and can not be included [or even remotely attributed] here.
Chris
Norfolk, VA, USA
Golden says:
Oh yeah, you have something in the US that we don’t have in the Bahamas… Doppler radar systems that will warn you ASAP of any suspected rotation. We just listen for the train.
====================
Doppler radar systems are not fail safe in their indication of tornadoes.
As a matter of fact, many a wasted tornado warnings cloud the airwaves with cry wolfers, thanks to the invention of “doppler indicated radar.”
No….you don’t listen for the train….and you have no idea what the train is like. I have never seen one of these filmed over the Bahamas.
And neither have you.
ALSO….From the Bahamian….
http://news.thebahamian.com/
“A new Doppler Radar system was commissioned yesterday at The Nassau International Airport. The new system will significantly improve the accuracy of weather reporting in The Bahamas. The new Doppler system will assist in the monitoring of major rain bands, provide vital information on the location, intensity and movement of both thunderstorms and tropical typhoons. As a result of the installation of this new system, meteorologists will now be able to monitor weather up to 300 miles from its base in New Providence.”
You don’t have doppler radar?
Chris
Norfolk, VA, USA
Re Mike M says: April 29, 2011 at 12:17 pm
It’s one of those things that could be technically feasible, but has issues around it. Typical cell sizes range from <1km to 50km radius depending on frequency and power, so may not be appropriate for directional warnings. General warnings would be more feasible.
The emergency warning centre, say NWS would then need to have a cell map overlaying the storm track(s) and decide which cells to warn. The type of warning message can be limited by the technology, so a cell base station won't have enough channels to play a warning message to everyone simultaneously so may have to stagger calling or just send text messages which could be delayed or ignored. If it has to use SMS texts, that limits the amount of information communicated. People in affected cells may also try to make calls, which could limit capacity but in emergencies cell networks can restrict calls to emergency or authorised phones only. But for an emergency service, it would need humans in the loop to decide which cells to warn, which may take time and in a fast developing/moving event like this may not be enough time.
It also assumes people have cell phones, and as Bowen points out, not everyone has access to technology. It also assumes the cell network is operational. Given they rely on transmitter masts, those may be blown down or damaged early on. They may lose power, or connection to the rest of the network, especially if they're using microwave or caternary cabling for backhaul. In a big event, the network providing the backhaul may also go down. Mobile networks are pretty vulnerable to disruption and damage. Post event, there's stuff like this-
http://en.wikipedia.org/wiki/Cell_on_wheels
to restore service but they take time to deploy if access is limited by damage. The bigger problem is still how to warn as many people as possible when technology means they may not be watching TV, listening to the radio, or have any reliable connection to a network. In population centres, lo-tech solutions like PA systems or sirens, but that's not feasible in rural areas.
There are also political and economic issues, like who pays for it and liability concerns. I've also encountered other political problems. I worked on ways to improve emergency comms for fire management and one problem was trying to protect mast sites. We wanted scrub cleared 10m around the sites for firebreaks, but couldn't because the scrub was protected. Go figure.
Many of the areas that were affected by tornados had already lost power so the residents didn’t have television or radio (unless battery powered) to warn them. Also, in some areas the tornado sirens actually were not working due to the storms before the tornados even hit so their warning system was destroyed.
A few previous commenters mentioned housing being a problem. Since Tuscaloosa is home to the University of Alabama there are tons of apartment complexes in the area that are occupied by students. Apartments are obviously not the safest place to be during a tornado so that made the situation more dangerous for residents; however, from seeing the damage first hand in numerous of the hit areas- it would not have made a huge difference if you were in an apartment or house.
Incredible devastation. You have to see it to understand it. I was there when it happened and videoed it.