a critical question for NOLA and the lake..........

[weatherwindow]

if the 500am track verifies, the closest point of approach to NOLA is 12 miles due east and over the eastern end of the lake.....that would subject the city and the lake to the northwest eyewall with persistent northerly winds.....is this the worst case scenario for the lake levees and city flooding ......rich

[dolebot_Broward_NW]

With the NHC predicting 15-20 feet of storm surge, and locally to 25 feet, I would say........ Yes. Increasing the average height of that lake by even a few feet would be catastrophic. I've never been there, and I don't know how big the levees are, but I bet they aren't 15 feet high, and the water isn't 15 feet below the lip.

Imagine filling your bathtub to within a few inches of the very top. Now suddenly lower the lip of the bathtub by a foot. Water everywhere. Now spray a firehose in the water. Keep it up for 24 hours.

Increase scale by several orders of magnitude, and you have the city under 10 feet of water in short order.

[milankovitch]

Depending on where this lands the southern levees may also be at a signigicant risk of being topped.

[dolebot_Broward_NW]

The levee system is at 12 feet from what I read, and the pictures I just saw support that. The lake is 630 square miles. Minimum forecast storm surge is 15 feet. Multiply 3 feet times 632 square miles and thats an idea of how much water will be dealt with. Hmm 1,896 cubic miles of water. Now over time the storm surge will tend to continue, so the entire time the storm surge is over 12 feet, the water will be spilling out.

Certainly a test of man vs. nature. Will the levee hold? Or will it break spilling 12 more feet of storm surge out? It would be almost as bad as say Hoover Dam busting.

[goodlife]

The levee system was 12 ft. back when it was built....it's more like maybe 9 ft. now from what the mayor said....he said the levee's settled and sunk a bit.

[dolebot_Broward_NW]

Oh good lord............ I'm not religious but I'm praying for everyone... I met this storm in south florida, and it wasn't normal. I caught the weak side, and it was like nothing I'd ever experienced. Still hundreds of thousands here without power. Frances and Jeanne, and even Irene don't hold a candle to the wind and rain I saw here. I wasn't here for Andrew but a lot of people here say that in N. Dade county this storm was far worse than Andrew was. Hopefully its a wakeup call to everyone new here.

God help us all.

[Big-Iguana]

15-20 foot storm surge and a 9 foot high wall, not hard to figure out.

Nola is in God's hands now...

[tronbunny]

I do not wish to invalidate the academic value of your question.. but, IMHO a strike by a cat 4 or 5 of this size within 50 miles of NO/Ponchartrain will have devastating effects on any community around the levees.

Storm surge of 15 ft with winds and rain just means horrible flooding - period.

This IS the "doomsday" scenario for NOL and southern LA. This event will change that coastline and could potentially require a LARGE percentage of NOLA residents to relocate permanently.

[dolebot_Broward_NW]

Lest we forget the economic impact of this storm. If I recall, NO is a MAJOR port of activity. In fact I seem to recall reading that NO handles nearly 50% of our oil imports. The Louisiana Offshore Oil Port, or LOOP is based around there and handles a good portion of our oil, which in turn is turned into GAS. So a direct hit will likely have a serious impact on all our pocketbooks. As if gas weren't high enough already. Imagine when half of the daily imports are gone. Oh dear lord.

[JenyEliza]

Lest we forget the economic impact of this storm. If I recall, NO is a MAJOR port of activity. In fact I seem to recall reading that NO handles nearly 50% of our oil imports. The Louisiana Offshore Oil Port, or LOOP is based around there and handles a good portion of our oil, which in turn is turned into GAS. So a direct hit will likely have a serious impact on all our pocketbooks. As if gas weren't high enough already. Imagine when half of the daily imports are gone. Oh dear lord.

Well, its just about a foregone conclusion that we're all going to eat a big jump in gasoline prices after Katrina. I'd guess we'll see $3.00 - $3.50/gallon, maybe more. But that's really neither here nor there at this point (at least to me).

I'm not so much worried about petrol prices at the moment. Life and limb is what's on my mind this morning. We can worry about our pocketbooks later.

Anyone who survives this would gladly pay twice the price and be grateful to be alive.

Not that you aren't raising a very valid point, but let's focus on life safety first....economics later.

Jen

[The Big Dog]

Imagine filling your bathtub to within a few inches of the very top. Now suddenly lower the lip of the bathtub by a foot. Water everywhere. Now spray a firehose in the water. Keep it up for 24 hours.

Increase scale by several orders of magnitude, and you have the city under 10 feet of water in short order.

More appropriately, put a washtub inside the bathtub, then fill the bathtub until it's over the top of the washtub. You don't just get a little bit inside the washtub -- it fills it completely.

New Orleans is in the washtub. I fear 10 feet is wishful thinking, considering a possible 20-25 foot surge into a city 5 feet below sea level in places. 30 feet of water is entirely possible.