Katrina was weaker than first thought (was Category 3 storm)

they are being built to withstand Category 3, which I just don't understand, as NOLA could get a Category 4 or 5 any time.

for that"....

it was the amount of rainfall that caused the levies to break not the wind. rainfall amounts can vary during hurricanes. both would need to be taken into account if they are to be rebuilt.

their beachfront houses before the flood came in.

Insurance companies get to keep the premiums and skate on the payout

Link:
http://www.sunherald.com/mld/sunherald/13454363.htm


:smoke:

The canals had been dredged not too long ago, and the deep dredging undermined the earthworks base, leaving nothing but a thin concrete shell between the Ninth Ward and total disaster.

It seems now that it didn't even need a hurricane. Doing a quick, cheap, stopgap job because Federal dollars had been squandered on war instead of on infrastructure doomed the city.

We have to get promilitary, anti American conservatives from both parties out of government. We can't survive them much longer.

that the Saffir/Simpson Scale isn’t worth the paper it is printed on. I was in the direct path of Ivan and Dennis, both were the same category storm, the devestation of the two storms can’t even be compared. Hurricane Dennis was far milder, and I mean no disrespect to people that suffered losses to Dennis. Ivan literally changed landscapes, Dennis, I stood on my front porch with a camera and filmed. I was in the right front quadrant for both.

Wind speed is important in a hurricane as a general estimate of strength, but other factors enter in, such as size of the storm, speed as it approaches landfall, and pressure. Wind speed and speed of the storm both contribute to the storm surge, and to the length of time a storm is in an area, so a fast Category three might be less devestating than a slow Category two.

The people who said all this didn't get much support before Katrina, but I suspect that now, especially with the downgrading of it, more people will listen.

Not questioning you, I would like to hear more about it.

I heard it as the dying gasp of the PBS News Hour when I tuned in early one night.

All I can find on dredging canals and Katrina is the story about the Mississippi River-Gulf Outlet Canal which they are planning not to dredge, because it caused much of hte flooding of the Lower Ninth Ward, and some of St Bernard Parish. I haven't found anything about dredging the Industrial Canal causing the levee to weaken. There's no doubt the levee was topped--there is video footage of water rushing over it in other places.

On PBS, all I can find is a story on NOVA about how dredging and canals have destroyed the wetlands, which increases the storm surge.

The 17th Street Canal levee, mentioned in your link, crumbled at the end and after the storm, and it slowly flooded New Orleans around downtown. This one was north of the city, near the lake, and flooded a middle class neighborhood, before slowly flooding downtown.

The one that broke and flooded the Ninth Ward was on the Industrial Canal, and it broke at the beginning of the hurricane, and caused most of the deaths. That's the one that flooded again during Rita's rainfall.

The levee on the Industrial Canal was topped by the storm surge, which, rather than coming up the lake or the river, was channeled directly from the Gulf by a smaller canal. Once a levee is topped it has a much greater chance of failure. The crucial factor in it was the storm surge, not rainfall or wind, but the whole surge might not have been as devestating without the smaller channel fromthe Gulf. That channel was partially filled in, and they are refusing to dredge it back out until they decide what to do. Some want a lock or floodgate to protect the Industrial Canal, others want it filled in permanently.

The industrial canal breeches I saw appeared to be classic overtopping.

The more I learn about the flaws in the 17th St. levee, the more I feel it was a disaster waiting to happen. It could just as well have broken following a heavy rain, with Pump Station No. 6 going all out, pushing against a high tide in the canal.

Imagine if this would have happened in the middle of the night, without 80% of the population evacuated.

a category 5 though. That wouldn't have abated that quickly.

The surge that hit the East side (St.Bernard Parish?) and the Mississippi coast was a Cat. 4 or 5 surge. The storm weakened just before landfall, but the large surge, compounded by the topography of the seafloor, kept on coming.

That said, everything West of the Industrial Canal should have stayed dry if it were not for faulty levees.

...and as far as the survivors along the Mississippi Coast are concerned, Katrina was a much stronger storm than Camille.

It seems like they're saying Cat 3 now to try to push all the damage and descriutction as not bringh as bad as it was.

Next they'll say the LEvee's didn't fail as well.

...You know, the surge that broke Cat 5 Camille's record surge of 25-28 feet.

I don't know why they're attempting to downgrade Katrina to a Cat 3. I thought if they were going to do anything they would have upgraded it to a Cat 5 based on the amount of widespread catastrophic damage across three states.

IMHO, this is crap.

it has to do with the fact that they want to be acurate in terms of the scale they are using. They do not claim that the 'catagory' is the sole determining factor in damage or anything like it. As another poster mentioned some scientists/meteoroligists want a new system of catagorization. But scientists being scientists they have a pesky desire to know the facts of a situation. If it was catagory 3 at landfal it was catagory 3... damage does not enter the equasion... only wind speed.

This gives them acurate data points to work with. They can say gee... a catagory 4 or 5 that downs all the way to a 3 can do all this damage... What other traits did it have?
That leads to new ways to measure the damage potential etc.

I do not think the scientists are full of crap when it comes to applying their measures. The Catagory system may be full of crap... the press who mis-represent the meaning of scientific data and claims may be full of crap... and the public who are unwilling to put any nominal amount of effort into understanding what an expert is actualy talking about when they make a statment... well they are definately full of crap.
But I would not blame the scientists who are hard at work studing the storm for noteing that gee... looks like the wind speed was lower than we thought before... gee.... that means it was a catagory 3 storm not a 4.... interesting.

Especially since they upgraded Andrew after the fact. I still think it was a 4 at landfall and a 3 when it struck Mississippi. You know I wish they would stop depending on the models and survey the actual damage. Computer models are only as good as the people that program them. If the wind gauges and buoys failed, wouldn't you call that a clue?!

In New Orleans, windows were blow out of buildings and the roof ripped off the Superdome amongst other things. Now we have had many small hurricanes strike the area ,but none have come close to the wind damage that Katrina inflicted.

My mom thinks this is political and I agree. They just don't want to spend the money on jacking up the levees.

A Cat 3 at landfall doesn't mean the storm surge was a Cat 3 too. The intensity of the storm surge is created father out to sea, when the hurricane is much stronger. So even though the winds may eventually decrease, the surge does not.

than that.
ASL, above sea level, Lake Ponchartrain
because of wave issues, the tops of some barriers wrer higher

the Orleans Levee District, which make projest decisions,
got esentially what they ordered.

the fact that the Levee District did not put
flood gates on the 17th St canal, is a tragedy

if anyone is interested, I will post links