Barrier Islands before and after

[LSU2001]

Here is a good site that shows the Chandeleur Islands before Ivan, Dennis, Katrina, and Rita and the same Islands after the above storms. This onslaught has caused severe damage to the chain and this does not bode well for future storms impacting La. Miss. and Ala.
http://coastal.er.usgs.gov/hurricanes/k ... eleur.html

Mods, I did not know if I should post this here or in Aftermath and Recovery so I will post in both. Please delete if it should not be in this forum.
TIm

[TheShrimper]

Great before and after pic's, but the results are to be expected. These islands, spoil areas are just a few feet above sea level, if they are indeed similar to the ones here in SW Fl. They were caused by storms and will be taken away by them as well. The only reason they exist is because storms or severe weather events have not taken them out. The only difference down here is that people have built on them. If a major storm hit Ft. Myers Beach, Sanibel or any of the Sarasota barrier islands, the results would be the same, if not worse. Where once there were mangroves, there now are none..nothing to break the flow of tidal surge. Charley was not a typical hurricane, it was a freak storm with no effects except winds in a small area. If Katrina took Chucks path at a slower clip there would be nothing left of the barrier islands south of Boca Grande. That includes Bonita, Ft. Myers beach..Sanibel, Captiva, Ussepa and Cayo Costa. Naples has no barrier buffers so to speak which is good and bad. If they had them, they would have been developed to the Naples extreme, adding to the potential devistation. Seeing that they do not, the mainland and all the exclusiveness, now wears the bulls eye. And do not bring up Wilma..there was little damage in Collier County, leading me to doubt the intensity of the storm.

[MiamiensisWx]

Great before and after pic's, but the results are to be expected. These islands, spoil areas are just a few feet above sea level, if they are indeed similar to the ones here in SW Fl. They were caused by storms and will be taken away by them as well. The only reason they exist is because storms or severe weather events have not taken them out. The only difference down here is that people have built on them. If a major storm hit Ft. Myers Beach, Sanibel or any of the Sarasota barrier islands, the results would be the same, if not worse. Where once there were mangroves, there now are none..nothing to break the flow of tidal surge. Charley was not a typical hurricane, it was a freak storm with no effects except winds in a small area. If Katrina took Chucks path at a slower clip there would be nothing left of the barrier islands south of Boca Grande. That includes Bonita, Ft. Myers beach..Sanibel, Captiva, Ussepa and Cayo Costa. Naples has no barrier buffers so to speak which is good and bad. If they had them, they would have been developed to the Naples extreme, adding to the potential devistation. Seeing that they do not, the mainland and all the exclusiveness, now wears the bulls eye. And do not bring up Wilma..there was little damage in Collier County, leading me to doubt the intensity of the storm.

Huh? You doubt Wilma's intensity at Florida landfall? The reason why the highest sustained winds of Wilma were not experienced was because they were in sparsely populated areas when the storm made landfall in southwest Florida. Just because little damage was reported on Marco Island and in Naples does not mean that Wilma was not a Category Three at landfall. Those areas were just spared the highest winds, which were in much less populated areas (e.g., the Ten Thousand Islands and the Everglades). Wilma was clearly a Category Three with sustained winds at landfall likely AT LEAST 120MPH to 125MPH.

[Matt-hurricanewatcher]

There was a recon as it was moving in that had high enough winds to support Wilma as a cat4.

[MGC]

The Chandeleur Islands are the remnants of a old Mississippi River delta. Several thousand years ago, the Mississippi emptied into the GOM well to the north of its current position. The gentilly ridge in New Orleans is the old river bank. The islands are slowly migrating westward......MGC

[wxman57]

Great before and after pic's, but the results are to be expected. These islands, spoil areas are just a few feet above sea level, if they are indeed similar to the ones here in SW Fl. They were caused by storms and will be taken away by them as well. The only reason they exist is because storms or severe weather events have not taken them out. The only difference down here is that people have built on them. If a major storm hit Ft. Myers Beach, Sanibel or any of the Sarasota barrier islands, the results would be the same, if not worse. Where once there were mangroves, there now are none..nothing to break the flow of tidal surge. Charley was not a typical hurricane, it was a freak storm with no effects except winds in a small area. If Katrina took Chucks path at a slower clip there would be nothing left of the barrier islands south of Boca Grande. That includes Bonita, Ft. Myers beach..Sanibel, Captiva, Ussepa and Cayo Costa. Naples has no barrier buffers so to speak which is good and bad. If they had them, they would have been developed to the Naples extreme, adding to the potential devistation. Seeing that they do not, the mainland and all the exclusiveness, now wears the bulls eye. And do not bring up Wilma..there was little damage in Collier County, leading me to doubt the intensity of the storm.

Huh? You doubt Wilma's intensity at Florida landfall? The reason why the highest sustained winds of Wilma were not experienced was because they were in sparsely populated areas when the storm made landfall in southwest Florida. Just because little damage was reported on Marco Island and in Naples does not mean that Wilma was not a Category Three at landfall. Those areas were just spared the highest winds, which were in much less populated areas (e.g., the Ten Thousand Islands and the Everglades). Wilma was clearly a Category Three with sustained winds at landfall likely AT LEAST 120MPH to 125MPH.

You're confusing storm surge damage and wind damage. Wilma did produce as significant an area of 75-100 mph winds inland as did Katrina. The big difference was that Wilma did not have a significant storm surge, so the barrier islands survived. I see on the Naples Hurricane Wilma post-storm report that a surge of 13-18 feet was "forecast". However, at Chokoloskee, a surge of 16 feet was forecast and the observed surge was only 7 ft.

If Katrina had moved ashore with Wilma's storm surge, then most of the MS coast would still be there. There would be a lot of power outages, but the structures would have received minimal wind damage for the most part. I've driven through south MS a number of times since Katrina. Almost all the significant damage was from surge, not wind. A few trees blown over (not as many as from Elena or Frederic). Mostly, what I saw was a lot of signs destroyed and minimal roof damage from Katrina's winds.

There are several reasons for Wilma's much-lower storm surge. First, there was limited fetch and duration. Wilma's southeast quadrant extended across Cuba, limiting the distance that the winds blowing toward Florida had over water. Wilma was accelerating NE across the SE Gulf, so the duration was limited as well. Katrina had been producing 50-60 foot waves across the Gulf. These waves moved into the MS coast prior to the arrival of the storm surge, creating a setup tide of probably 5-8 feet above MSL. No such setup for Wilma. Bottom line is that Wilma and Katrina really weren't that different wind-wise (intensity and areal coverage of winds) at landfall. Katrina's massive 30+ foot surge was the difference.

[Brent]

WOW...

[Pearl River]

Unfortunately, the entire Louisiana coast is begining to like like the Chandeleurs.

[Derek Ortt]

Chris,
the low surge in Everglades City was because the winds were offshore. The surge in mianland Monroe did come 20 miles inland... its just that there are 8 residents of mainland Monroe (that is not an exaggeration of the population, thats the actual full time population of the county; thus, nobody was affected by the surge

[aerojad]

Lesson: don't build on barrier islands.

[Margie]

Actually NCDDC has a very good impact assessment site that also includes some before/after of barrier islands along the MS Gulf Coast:

http://www.ncddc.noaa.gov/Katrina/

[Margie]

I've driven through south MS a number of times since Katrina. Almost all the significant damage was from surge, not wind. A few trees blown over (not as many as from Elena or Frederic). Mostly, what I saw was a lot of signs destroyed and minimal roof damage from Katrina's winds.

The direct surge damage was limited to the lower 10 miles of the coast (amazing that in some places the surge reached that far).

There was a great deal of wind damage from Katrina in coastal and inland MS, once inland from the immediate coast, throughout the lower third of the state. There was over 50% blowdown of forests in the three coastal counties, and a significant % blowdown in the next three counties. Forestry and pecan industries were severely affected in George County, for example.

It didn't make the news except locally because of the extreme devastation of the coastline. There were quite a few people living in shelters for some time, who did not live on the coast, for instance, in Hattiesburg, due to wind damage inland.

Go to the FEMA website to find the MS counties that were affected by Katrina (the entire southern half of the state).

The AOML models, and also some radar images from the MOB NWS, of Katrina, demonstrate how far inland the damaging winds occured.

With both Ivan and Katrina, even Birmingham, AL experienced significant winds.

Please don't interpret this to mean that I am talking about sustained winds above Cat 2 level, with higher gusts. I have heard from a reliable source that some Cat 3 wind damage did occur around Hwy 49 just a little inland from coastal Gulfport / Biloxi area.

[GeneratorPower]

Lesson: don't build on barrier islands.

I disagree... the lesson is: if you build on barrier islands, be prepared to evacuate and be prepared to lose everything. And don't expect anyone else to give you rebuilding money.

[Dr. Jonah Rainwater]

Don't these barrier islands tend to rebuild themselves after a hurricane strike? Mother Nature doesn't usually destroy herself without a larger balance.

[Margie]

Don't these barrier islands tend to rebuild themselves after a hurricane strike? Mother Nature doesn't usually destroy herself without a larger balance.

Not always. Sometimes the island creeps northward (this is happening a bit with what is left of the western end of Dauphin Island).

However more often the islands are losing ground, literally.

With Camille, for instance, "Two islands lost more than 300 acres to erosion, and the third, Ship Island, was breached." Since Camille, Ship Island has remained two separate islands.

Ivan and Katrina did further damage to all the islands of the MS Sound.

[Jim Cantore]

is there even anything (anyone) on the Chandeleur Islands?

[Margie]

is there even anything (anyone) on the Chandeleur Islands?

The value of the islands does not lie in any possible real estate development value for homo sapiens. As barrier islands they provided an essential buffer from storms. They also provided a home to plant and animal life specific to the region; a "vital role in the Gulf ecosystem."

At least half of the island chain is gone as a result of Katrina, but part of the reason for this is that last year Ivan destroyed a great deal of the vegetation, resulting in sand that was easier to wash away.

http://www.laseagrant.org/hurricane/wetlands.htm

http://news.nationalgeographic.com/news ... delta.html

[ROCK]

is there even anything (anyone) on the Chandeleur Islands?

No, there was a light house on the north end but I supposed its toast now. Sad to see since I have been fishing there and actually camped on the islands over a weekend. Suffice to say fishing will never be the same.

[CajunMama]

If i'm not mistaken man is the main reason the Chandeleur Islands are gone. When man redirected the Mississippi River all the silt that would have built up along the coastline was gone.

[Margie]

If i'm not mistaken man is the main reason the Chandeleur Islands are gone. When man redirected the Mississippi River all the silt that would have built up along the coastline was gone.

That's correct.