Hurricane Isaac hits Louisiana, driving dangerous storm surges

By: Dr. Jeff Masters , 2:27 AM GMT on August 29, 2012

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Hurricane Isaac is ashore over Southeast Louisiana, having officially crossed the coast on the Mississippi Delta 90 miles southeast of New Orleans at 7:45 am EDT on August 28. Isaac intensified right up until landfall, striking with 80 mph winds and a central pressure of 970 mb. The storm's large size and large 50 - 60 mile diameter eye kept the intensification rate slow today, but it came quite close to becoming a significantly more dangerous storm. That's because at landfall, Isaac was in the midst of establishing a small inner eyewall within its large 50-mile diameter eye, a very rare feat I've never seen before. Usually, when an eye first forms, it gradually contracts, eventually becoming so small that it becomes unstable. An outer concentric eyewall then forms around the small inner eyewall, eventually becoming the only eyewall when the inner eyewall collapses. But Isaac is a very unusual storm that has continually surprised us, and this inside-out concentric eyewall formation fits the storm's unusual character. The storm isn't in a hurry to move fully inland, and has slowed down to a crawl this evening. This will give the storm the opportunity to keep its center mostly over water a few more hours, and maintain hurricane strength into the early morning on Wednesday.


Figure 1. Radar reflectivity image from New Orleans as Isaac made landfall at 6 pm CDT August 28, 2012.

A dangerous storm surge event underway
Isaac is bringing large and dangerous storm surge to the coast from Central Louisiana to the Panhandle of Florida. At 10 pm EDT, here were some of the storm surge values being recorded at NOAA tide gauges:

6.2' Waveland, MS
9.9' Shell Beach, LA
3.0' Pensacola, FL
4.4' Pascagoula, MS
3.4' Mobile, AL

The 9.9' storm surge at Shell Beach, which is in Lake Borgne 20 miles southeast of New Orleans, exceeds the 9.5' surge recorded there during Category 2 Hurricane Gustav of 2008. Research scientists running a Doppler on Wheels radar located on top of the 16' levees in Plaquemines Parish near Port Sulphur, LA, reported at 8:30 pm EDT that a storm surge of 14' moved up the Mississippi River, and was just 2' below the levees. Waves on top of the surge were cresting over the west side of the levee. Needless to say, they were very nervous. Over the past hour, the surge has retreated some, and waves were no longer lapping over the top of the levee. This is probably due to the fact that we're headed towards low tide. A storm surge of 9.5' has moved up the Mississippi River to the Carrrollton gauge in New Orleans. This is not a concern for the levees in New Orleans, since the storm surge has now brought the river up to 2.5' above its normal water level, which was 7' low due to the 2012 U.S. drought. The highest rise of the water above ground level will occur Wednesday morning over much of Southeast Louisiana, Mississippi, Alabama, and the western Florida Panhandle, when the tide comes back in. It is clear now that this storm surge event will be as dangerous as that of Category 2 Hurricane Gustav of 2008. One piece of good news: NWS New Orleans successfully launched their 00Z balloon. However, their discussion noted the atmosphere is "saturated or nearly saturated" all the way up to 470mb, or 20,000 feet. Precipitable water was 2.76 inches, which will be ripe for extremely heavy rainfall.


Figure 2. Tide gauge data from Shell Beach, located on the south shore of Lake Borgne, just east of New Orleans. The green line shows the storm surge. The red line is the storm tide, the height of the water above Mean Sea Level (MSL.)

Portlight disaster relief charity responds to Issac
The Portlight.org disaster relief charity, founded and staffed by members of the wunderground community, have mobilized resources in advance of the arrival of Hurricane Isaac. Their crew, including 2 EMTs, is at the Biloxi Special Needs Shelter, and will be caring for shelter dwellers and doing rescues of people who call for help. Another team will be surveying all the shelters in the area to ensure that they are accessible to all people. You can donate to Portlight's disaster relief fund here.

I'll have more in the morning. Hunker down, New Orleans. It's going to be a long night.

Jeff Masters

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Quoting alaina1085:
img src="">
Unbelievable...

Can't see it.
Member Since: June 21, 2007 Posts: 10 Comments: 1657
Quoting alaina1085:
img src="">
Unbelievable...


Ur video is unavailable :/
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1717. LargoFl
flooding is going to be the Real issue with Isaac long after he is gone
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Quoting TomballTXPride:
The good news with Isaac is this is the first time now in a while that the clouds are beginning to warm significantly around the center. Hopefully enough to collapse the eyewall and bring him down to a TS by 10 AM. As a result though, the wind field could still expand, but the intensity will be decreasing very soon.

Link


Maybe, but I think he needs to get away from the coast first. As long as he is paralleling the coastline he is going to be able to bring in energy from the east, south, and points southwest. As long has he has those within reaching distance he going to maintain structure for a longer period. He could stay at hurricane strength until this afternoon.
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img src="">
Unbelievable...
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Good Morning and Godspeed to all the folks in LA/MS/AL dealing with this storm and the local heroes in their boats giving the Coast Guard-Local Authorities a run for their money. Incredible how little the storm has moved and not weakened much. Praying that the levee pumps can keep up with all the rain.
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Morning guys... hey I need some help to explain the models. When I pulled up the water vapor imagery of the Central United States, that's all i see is a bunch of dry air sweeping directly south from the plains making a head-on collision with Isaac. How in the world does Isaac turn North all the way up to midwest? What in the world am I missing??? I don't see anything in the water vapor imagery to confirm this predicted move to the north. I would greatly appreciate any hints/remarks.

On a side note, the sun is out in Charleston S.C. this morning heating up the atmosphere again. Ohhh boy, this is trouble, round two this afternoon.
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Quoting alaina1085:


No joke, im uploading a pic. Gimme a sec


No, seriously.........you don't have to........or want you to! HA
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Quoting mikatnight:
Sounds like some of the ladies might nhave a bit of a crush on Mr. Cantore...
Cantore calenders on the wall perhaps?


ABSOLUTELY NOT! (---says kctinney as she chokes back the bile...............
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1708. Jaevyn
Quoting TomballTXPride:
The good news with Isaac is this is the first time now in a while that the clouds are beginning to warm significantly around the center. Hopefully enough to collapse the eyewall and bring him down to a TS by 10 AM. As a result though, the wind field could still expand, but the intensity will be decreasing very soon.

Link


That is unlikely to happen, while Isaac is technically over land, this land is swampy. That and I cannot see any evidence of any significantly warming cloud tops.
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Quoting Kristina40:


Please tell me you are joking? Please?


No joke, im uploading a pic. Gimme a sec
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1706. KEEPEROFTHEGATE (Mod)
Member Since: July 15, 2006 Posts: 169 Comments: 53308
Quoting reedzone:
Looks like Isaac has lived up to its reputation.. I personally believe the storm became a Category 2 last night as winds gusts reported around 120 mph in some areas. I don't believe a Category 1 can produce that much wind. Anyways, awkward to believe this is happening 7 years ago after Hurricane Katrina.. Just odd.
I think after the season ends, it will be reclassified to be a Category 2, along with Gordon being a Category 3 and adding an unnamed system. Beryl might become a hurricane, as well.
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1704. ncstorm
Isaac

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Quoting LargoFl:
@WWLTV private citizens rescuing braithwaite citizens (s of new orleans in plaquemines parish) who are stuck on their roof tops. ..sorry..cant post the flash video..grrrr
This is why I love the true Gulf Coast. There is a need and local heroes step up. God bless them!
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Quoting alaina1085:
OMG I have seen it all, Cantore was doing push ups in the middle of Canal street in the wind and rain...wow...


He thought he was off air at the time. You could see him fooling around with the camera men.
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1701. LargoFl
Cohn street flooding....
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Quoting Kristina40:


Please tell me you are joking? Please?


Doesn't he know that only Chuck Norris does pushups in a hurricane? Jeez lol.
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Sounds like some of the ladies might nhave a bit of a crush on Mr. Cantore...
Cantore calenders on the wall perhaps?
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Looks like Isaac has lived up to its reputation.. I personally believe the storm became a Category 2 last night as winds gusts reported around 120 mph in some areas. I don't believe a Category 1 can produce that much wind. Anyways, awkward to believe this is happening 7 years ago after Hurricane Katrina.. Just odd.
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1695. GetReal
Quoting presslord:
Isn't the tidal range in that part of the world fairly low? Like....a foot or two....if so, that'll help...


Yes...
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Quoting presslord:
Isn't the tidal range in that part of the world fairly low? Like....a foot or two....if so, that'll help...


We hardly ever get a tide of over 2 feet here, so yes, relatively low. However, the land is very low, too!
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Wind picking up and water nearing US-90 at one of the higher locations along 90 between Biloxi, and Gulfport. Live webcam.
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Model runs for 98L are too far east...watch them shift west over the coming runs.

This is exactly how Isaac's early model runs looked and we see how that turned out.

Anyways, with Isaac making landfall on the Central Gulf Coast, we'll have another one either next month or October. They always come in pairs...Katrina/Rita...Gustav/Ike.

There are probably more.
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an observation...Isaac looks to still be moving more West than NW. Once Isaac passes the "land" area now, it will be close to Vermillion Bay...this will only cause him to be back over open water. Is there any N movement with him right now?

Here in Lafayette...no ran yet.. good wind gusts up to 40mph (not sustained)
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Quoting alaina1085:
OMG I have seen it all, Cantore was doing push ups in the middle of Canal street in the wind and rain...wow...


Please tell me you are joking? Please?
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Quoting MTWX:


We had to sleep in shifts after the tornado outbreak last year to protect the neighborhoods generators. Once night falls the looters came out in full force. Once they realized they were be watched by people with guns, they decided to go elsewhere!

Through out the 2 weeks we were there, we only lost 2 generators out of about 50. Both of those were taken in the middle of the day while we were making our rounds delivering supplies.


We have the gas for our generator along the pen for my German Shepherd with my son's truck in front of it hiding it from sight. As from my earlier post, I'm out in the country on a dead end road, anyone coming out here after a storm is up to no good.
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Live Storm Footage from Biloxi


Link
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Isn't the tidal range in that part of the world fairly low? Like....a foot or two....if so, that'll help...
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Granted things are bad now with Isaac but one has to step back for a minute and thank whomever your almighty power is for the adversity in the Atlantic and SE GOM.
Member Since: August 19, 2005 Posts: 5 Comments: 5043
OMG I have seen it all, Cantore was doing push ups in the middle of Canal street in the wind and rain...wow...
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1684. LargoFl
ROBERTSDALE, Alabama -- Assessment teams are scheduled to start checks this morning, but preliminary indications are that Baldwin County escaped major damage from Hurricane Isaac overnight, county officials said.

The Mobile Bay Causeway, Fort Morgan Road, Ala. 182 along the Gulf beach, and the south end of Ala. 59 were closed Wednesday morning, according to reports from the Baldwin County Emergency Management Agency.

Flood waters crossed Fort Morgan Road between mile markers four and five on the west end of the highway. The highway on the beach was closed from Ala. 135 at the Alabama Gulf State Park to the road's end on West Beach to restrict traffic due to high winds and to reduce sight-seers, officials said.

Other closings include Pelican Point Park and Baldwin County 1 on the Eastern Shore, Jubilee Point Road.

Damage assessment teams will be dispatched this morning from the Baldwin County Emergency Operations Center in Robertsdale, Paula Tillman, county spokeswoman, said.

The two public storm shelters took in 254 evacuees overnight, 181 in the Baldwin County Coliseum in Robertsdale and 73 at Daphne East Elementary School.
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1683. ncstorm
Quoting CloudGatherer:
According to CNN, the Affordable Care Act was struck down.

According to Entergy, there are currently 451,000 customers without power, and efforts at restoration won't begin until late tomorrow at the earliest.


from the same website you just posted..
Those numbers are fluctuating. Most of the customers will likely not have their lights for the remainder of the storm, utility officials say. Crews are not able to start repairs until winds drop below 30 or 35 mph, which is likely to be Thursday at the earliest.

From CNN:

09:17 AM ET
More than a half-million customers without electricity, utilities report

* Hurricane Isaac is dumping inches of water on Gulf Coast cities after smashing into land overnight
* Water has overtopped levees in Plaquemines Parish and officials fear %u201Cdeep flooding%u201D there
* The storm could take 12 hours to go from New Orleans 70 miles north to Baton Rouge
* More than 522,000 without power across four states

Refresh this page for the latest updates or read the full CNN story here.

[Updated 9:17 a.m. ET Wednesday] 522,228 customers are without power in Arkansas, Alabama, Louisiana and Mississippi, according to power providers Entergy, Alabama Power, and Cleco.

[Updated 9:15 a.m. ET Wednesday] The center of Hurricane Isaac is 40 miles southwest of New Orleans, the National Hurricane Center said in its latest advisory Wednesday. Strong squalls from the storm are battering southeastern Louisiana and heavy rains and a "dangerous storm surge" are likely to continue into the evening, the advisory said.

[Updated 9:14 a.m. ET Wednesday] An elderly Florida may have been disoriented from heavy rain associated with then-Tropical Storm Isaac when she drove into a retention pond and drowned Monday, CNN affiliate WFTV in Orlando reports.

The body of 89-year-old Margaret Langewisch was found in her Mazda in the 18-foot-deep pond in Winter Springs on Tuesday.

"We had a torrential downpour for 10 or 15 minutes and I think that's what the problem was because she must have missed the first right and thought she was going to the clubhouse," resident Tony Palmiotti is quoted as saying.

[Updated 9:07 a.m. ET Wednesday] Alabama Power reports that about 5,600 customers are without power, mostly on Dauphin Island, in Bayou la Batre and other areas in south Mobile County. Another 1,100 are without power in the Theodore area. Alabama Power says all customers should have power restored by day's end.

[Updated 9:05 a.m. ET Wednesday] With Isaac now moving at the torpid pace of 6 mph, National Hurricane Center Director Richard Knabb tells CNN that the storm's eye has yet to pass through the region and residents in the area can expect pounding rain "all day today, into tonight, into tomorrow."

"For many people, it's not even half over," Knabb said.

[Updated 9:01 a.m. ET Wednesday] As Isaac's winds and rain continue to hamper government services in Louisiana and Mississippi, the city of Pensacola, Florida, has announced it is back to business, according to CNN affiliate WALA. City Hall, libraries, garbage service and the Pensacola International Airport were all operational as of this morning, the station reported.

[Updated 8:53 a.m. ET Wednesday] Three adults and one infant in Mississippi were rescued overnight from a houseboat as Hurricane Isaac hit the region, the state's emergency operations center said Wednesday.
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Quoting mikatnight:


Not sure about that. Google "fish caught in fence". Supposedly it's...
"Fish remain stuck in a fence on September 15 as flood waters caused by Hurricane Ike recede, in West Orange, Texas
Picture: AP"


I think imkanight is right. I remember those pictures after Ike, after I got power back.
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Quoting all4hurricanes:

Then one of those countries would have to come to the WMO meeting and suggest it which Haiti almost never does and the Dominican didn't have anywhere near as many deaths. If Dr.Masters Prediction of 500mil-4bil dollars in damage is correct (or an underestimate) Isaac should be able to retire on damage alone.


i was wondering why gordon wasn't retired in '94, hundreds of deaths and they still use the name. thx
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A year ago I moved from Braithwaite to Alaska. This was my home for 3 years. It is underwater. I am texting with my neighbor from Bazile Drive and she is telling me there is 12 feet of water in her house (she isn't there) but there are people that stayed, mostly on the front of our street. Most of them are older people. Some are trapped in attics, some made it to the top of the levee. Braithwaite park is also underwater and people are trapped in their attics. This is so much bigger than Katrina for these people. My neighbor who only had 3 feet of water from Katrina, now has 12feet of water.
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Quoting Tazmanian:



Ok but I this hate it when evere one looks and the early mode runs and start yelling fish when they no vary well that things wil likey change 100s of times be for they set In done


94L was forecast too be a fish then. Look where it ended up going MX




With the same standard, you should be *poofed* for calling Isaac a Cat3 and Cat4 24-hours out when NHC said Cat1 landfall. If someone wants to call 98L or Kirk a fish storm, what's the diff? Even Norcross is calling these two new areas fish storms at the moment. Now get back into your crate and behave.
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Quoting mikatnight:


I realize that. I also find Largo's comments to be a welcome addition to the blog.

Just not that one. It sends the wrong message. Very,very wrong.

But, like I always say:

Dying is easy, comedy is hard.


Ah Ike. The pic is local. Some people were saving fish and gators. The latter took a bit more care of course.
Member Since: August 24, 2010 Posts: 0 Comments: 682
Quoting TomballTXPride:

Great point. Needs to be repeated.


Easy to judge when you don't walk in their shoes. Perhaps for the course of the storm, these comments should wait.

You will have plenty of time to bash people tomorrow.
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1674. MTWX
Quoting aislinnpaps:


After Rita we had a carload of teens drive down my deadend road with no lights at about 2 in the morning. They parked in the center of the only three houses here and got out, planning on looting. My one neighbor has a relative who is mentally challenged and sleeps whenever he is tired (He has a little one room 'house' on their property). He was up and they scared him so he went into the main house and woke them to say there were people outside in the dark. Those teens were then met with shotguns when they were ten feet from my door and about the same at the other closer house. This is redneck country, you don't mess with them!


We had to sleep in shifts after the tornado outbreak last year to protect the neighborhoods generators. Once night falls the looters came out in full force. Once they realized they were be watched by people with guns, they decided to go elsewhere!

Through out the 2 weeks we were there, we only lost 2 generators out of about 50. Both of those were taken in the middle of the day while we were making our rounds delivering supplies.
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CNN

Levee overtopped in Plaquemines Parish, Louisiana


-Hurricane Isaac is dumping inches of water on Gulf Coast cities after smashing into land overnight
-Water has overtopped levees in Plaquemines Parish and --officials fear “deep flooding” there
-The storm is almost stalled and could take 12 hours to go from New Orleans 70 miles north to Baton Rouge
-More than 486,000 without power in Louisiana.
Member Since: August 19, 2005 Posts: 5 Comments: 5043
1672. LargoFl
@WWLTV private citizens rescuing braithwaite citizens (s of new orleans in plaquemines parish) who are stuck on their roof tops. ..sorry..cant post the flash video..grrrr
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Quoting StormHype:


Now that is good. Fake obviously, but a clever, creative, and very funny pic! :-)


Not sure about that. Google "fish caught in fence". Supposedly it's...
"Fish remain stuck in a fence on September 15 as flood waters caused by Hurricane Ike recede, in West Orange, Texas
Picture: AP"
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Here is a twitter pic of the water undermining one of the floodwalls in Braithwaite,south of new orleans.

from a jornalist there: http://twitter.com/nolacameragirl/

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About

Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.