Quiet in the Atlantic; lessons learned from Hurricane Hugo's storm surge

By: Dr. Jeff Masters , 12:35 PM GMT on September 21, 2009

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The tropical disturbance (98L), midway between Africa and the Lesser Antilles Islands, has grown weak and disorganized. No development of this disturbance is likely to occur.

The remains of Hurricane Fred are still kicking up heavy thunderstorms about 400 miles east of the Georgia-Florida border. Fred-ex's circulation has become ill-defined, as seen in last night's QuikSCAT pass. Fred-ex is under about 20 knots of wind shear, and this shear is expected to remain about the same over the next two days. Fred-ex will be moving ashore Tuesday night or Wednesday along a stretch of coast from Florida to North Carolina, bringing heavy rains to some areas. There is too much wind shear and dry air, and not enough time, for Fred-ex to develop into a tropical depression. I don't expect it to cause any flooding problems when it moves ashore.


Figure 1. Morning visible satellite image of Fred-ex, 400 miles east of Florida.

Twenty years ago today
On September 21, 1989, Hurricane Hugo began the day as a minimum-strength Category 3 hurricane with 115 mph winds. But as a strong trough of low pressure turned the hurricane to the north and accelerated Hugo to a forward speed of 25 mph, the storm took advantage of low wind shear and warm ocean waters to begin a period of rapid intensification. As darkness fell on the 21st, Hugo had grown to huge Category 4 hurricane with 135 mph winds. Its target: the South Carolina coast near Charleston, at Sullivan's Island. At 11:57 pm on the 21st, Hugo made landfall on Sullivan's Island. It was the strongest hurricane on record to hit South Carolina, and the second strongest hurricane (since reliable records began in 1851) to hit the U.S. East Coast north of Florida. Only Hurricane Hazel of 1954 (Category 4, 140 mph winds) was stronger.


Figure 2. AVHRR visible satellite image of Hurricane Hugo taken on September 21, 1989. Hugo had intensified to a formidable Category 4 hurricane with 135 mph winds.

On Isle of Palms, a barrier island adjacent to Sullivan's Island, the mayor and several police officers were sheltering in a 2-story building which lay at an elevation of ten feet. As related in a story published in the St. Petersburg Times, they heard the following bulletin on the radio at 10:30pm the night Hugo made landfall:

"The National Weather Service has issued a storm surge update. It appears that the storm surge will be greater than anticipated. It is now expected to reach a height of 17 to 21 feet."

"Mom didn't raise an idiot," said the one cop with the most sense, and he convinced the others to get off the island. They left the island by driving at 5 mph through horizontal sheets of rain and hurricane-force wind gusts over the Ben Sawyer Bridge, which connected Sullivan's Island to the mainland. As they crossed onto the bridge, they passed over a large bump--the bridge and road bed were at different levels. Not good. While crossing the bridge, they could feel it swaying and straining, and heard the sound of metal, twisting and grinding and breaking. They made it, but only barely--minutes later, the hurricane tore the center span of the bridge from its connection on both ends, leaving it a twisted ruin in the bay.


Figure 3. The Ben Sawyer Bridge connecting Sullivan's Island to Charleston, South Carolina, after Hurricane Hugo. Image credit: NOAA Photo Library.

Hugo's storm surge
In McClellanville, on the coast thirty miles northeast of Charleston, between 500 - 1100 people took refuge at the designated shelter for the region, Lincoln High School. Lincoln High is a one-story school, mostly constructed of cinder block, located on the east side of Highway 17, and was believed to be at an altitude of twenty feet. McClellanville is about 4 - 5 miles inland from the open ocean, but lies on the Intracoastal Waterway, so is vulnerable to high storm surges. Near midnight on the 21st, a storm surge of twenty feet poured into Bulls Bay just south of McClellanville, and funneled into the narrow Intracoastal Waterway. Water started pouring into the high school and rose fairly rapidly. Within minutes, people were wading around up to their waists, the water still rising. In the school cafeteria, many refugees gathered on a stage at one end, putting children up on tables. The elevated stage kept them above water; others floated in the water. Another group was in the band room, which had a much lower ceiling than the cafeteria. They had to stand on desks and push out the ceiling tiles for more breathing room, as the water rose within 1 - 2 feet of the ceiling. Fortunately, Hugo's storm surge peaked at that time, at about 16 - 17 feet (Figure 4), and the people sheltering at Lincoln High were spared.


Figure 4. Estimated storm surge (height above ground) as estimated by NOAA's storm surge model, SLOSH. McClellanville (upper right) received a storm surge estimated at 16 - 17 feet.

According to Dr. Stephen Baig, the retired head of the NHC storm surge unit, the back-story is this: To build Lincoln High School, which lies at an altitude of ten feet, the local school board used the same plans that were drawn up for another school that is west of Highway 17, and that IS at 20 feet elevation. Not only the same plans, the same set of working drawings. Those working drawings showed a surveyed elevation of 20 feet above datum (probably NGVD29). Apparently Lincoln High was constructed either without benefit of elevation survey or the plans were not annotated with its site elevation. When the Red Cross inquired as to its utility as an evacuation site, whoever looked at the plans saw the surveyed elevation at 20 feet. That is what the Red Cross published. That is why the school was a designated shelter. Since that near-tragedy, the Red Cross requires a new elevation survey for every potential storm shelter. I think that at the time this was discovered all the designated shelters also were re-surveyed, just to be sure that no similar Lincoln High problems were waiting to happen.

Only one person died from Hugo's storm surge, a woman who sheltered in her mobile home that got struck by the surge. Her death was one of only ten deaths that have occurred due to storm surge in the U.S. in the 35 years between 1969 - 2005 (after the 100+ storm surge deaths due to Hurricane Camille of 1969, and before the 1000+ storm surge deaths due to Hurricane Katrina). This amazingly low death toll can be attributed to four factors:

1) Greater understanding of the storm surge and better storm surge forecasts issued by the National Hurricane Center, thanks to such tools as the SLOSH storm surge model.
2) The excellent job NWS/NHC/FEMA and state and local Emergency Managers have done educating the public on the potential surge they can expect.
3) The success local government has had making evacuations of low-lying areas work.
4) Luck. The 20+ storm surge deaths on the Bolivar Peninsula in 2008 from Hurricane Ike show that there are still plenty of stubborn, unlucky, or uneducated people who will die when a significant storm surge hits a low-lying populated coast. The storm surge from the next major hurricane that sweeps through the Florida Keys is likely to cause a lot of storm surge deaths, since many residents there are pretty stubborn about not evacuating.

Kudos and links
I thank Ken Bass for providing the details on the Lincoln High storm surge near-disaster. Ken is working on a book on Hurricane Hugo, and has written a very readable book I plan to review later this year, about a fictional Category 4 hurricane hitting New York City.

Hurricanes-blizzards-noreasters.com has a web page with links to tons of Hurricane Hugo stories. Included are links to YouTube videos of a "Rescue 911" episode that interviewed survivors of the Lincoln High storm surge scare. The show also did a re-creation of the event.

Our Historical storm surge page has SLOSH model storm surge animations of Hurricane Hugo's landafall, as well as of 39 other famous hurricanes.

Tomorrow: I'll wrap up my series on Hurricane Hugo.

Jeff Masters

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Quoting Chicklit:
Total Storm Precipitation Atlanta area.
Link

Serious, indeed. And more rain on the way.
Link


Hey Chiklit!! That is some link, not a good picture for Atlanteans.
Member Since: July 17, 2009 Posts: 69 Comments: 25458
327. Skyepony (Mod)
Thanks StormW but we already covered that.. It was on to how ENSO effects MJO.

What I've found, simply put, is the higher SST of EL NIno may cause more stability, supressing MJO~ causing it to be weaker. Which eventually leads to a switch in ENSO. There is some questions remaining about a decade cycle affecting the relationship as well. They don't seem to have this nailed down completely.
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317. bloodstar

That is so sad. :(
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TDWR High Definition Radar

Atlanta, Storm Total Surface Rainfall Accumulation Range 124 NMI

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Issued by The National Weather Service
Atlanta, GA
11 am EDT, Mon., Sep. 21, 2009

... FLOOD WARNING EXTENDED UNTIL TUESDAY AFTERNOON... THE FLOOD WARNING CONTINUES FOR THE CHATTAHOOCHEE RIVER NEAR VININGS AT PACES FERRY * UNTIL TUESDAY AFTERNOON. * AT 8 AM MONDAY THE STAGE WAS 18.0 FEET AND RISING. * MODERATE FLOODING IS OCCURRING AND MAJOR FLOODING IS FORECAST. * FLOOD STAGE IS 14.0 FEET. * THE RIVER WILL CONTINUE RISING TO NEAR 20.1 FEET BY THIS AFTERNOON. THE RIVER WILL FALL BELOW FLOOD STAGE LATE TOMORROW MORNING. * AT 20.0 FEET... MAJOR FLOODING BEGINS. MANY HOMES... NEARBY SHOPS... RESTAURANTS... AND LOVETT SCHOOL WILL BE FLOODED. HOMES FLOOD ALONG PACES FERRY SOUTHEAST DRIVE.

More Information

Didn't know it was that bad.
Member Since: July 17, 2009 Posts: 69 Comments: 25458
Quoting LBAR:


That's downright depressing! We're starving for rain in central South Carolina and North Carolina...


I know how you feel, we have had 0.07 inches of rain this month, and it has only rained twice all month, once on the third, and a little bit yesterday
Member Since: June 28, 2006 Posts: 24 Comments: 8201
322. LBAR
Quoting Chicklit:
Total Storm Precipitation Atlanta area.
Link

Serious, indeed.


That's downright depressing! We're starving for rain in central South Carolina and North Carolina...
Member Since: Posts: Comments:
Total Storm Precipitation Atlanta area.
Link

Serious, indeed. And more rain on the way.
Link
Member Since: July 11, 2006 Posts: 14 Comments: 11198
I do have to chuckle. Fred-ex looks like a pimple on Hugo's butt.

//Still living in Charleston and we need the rain Fred could bring.
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It is a tropical upper tropospheric trough (TUTT) over an upper cold low. Way up there.
Member Since: July 17, 2009 Posts: 69 Comments: 25458
Quoting sarahjola:

how so?


Massive rainfall, at this point it's being called a historic event. And the rain isn't stopping.

"The deluge of rain that closed schools, highways and railroads across metro Atlanta turned deadly Monday. Two people have been confirmed dead and emergency crews are searching for countless more reported missing amid the flooding waters."

http://www.ajc.com/news/flooding-claims-lives-search-142739.html

Travel is problematic and there are a number of people who were caught off guard by the flooding.

here's a current listing of road closures in the Atlanta Area
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Quoting pearlandaggie:
290. I don't know if you had a comment or picture for me. All I was able to see in your post was a quote of my post. If it was a picture, the corporate firewall probably ate it if it was shared from a personal storage website.


It was for you. Hurricaine Ivan destroyed the trees on the Ft Morgan penisula. Also all the dead trees in Gulf State park.
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good afternoon guys, had an interesting EAS class today, we talked about the impact that hurricanes have on the oil and natural gas industry, and I never realized how big the oil platforms are! wow
Member Since: June 28, 2006 Posts: 24 Comments: 8201
Quoting tropicofcancer:


Wow! tha's brutal! need the fronts to start getting down here soon.


Been a hot one this year, that's for sure. I can't wait for that first crisp fall day in the 70's. Heck I'd even do low 80's at this point.
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Quoting SCwannabe:


What is a TUTT?


I can't let this one go guy, please allow me.

You know, like the Egyptian King. Honestly, SCwannabe. Someone will provide you with the correct answer, I promise. Just a little levity.
Member Since: July 17, 2009 Posts: 69 Comments: 25458
Quoting OSUWXGUY:


Agreed.

Another important point is the simple, yet powerful effect of surface convergence. Air at the surface in a hurricane can be pulled in from many hundreds of miles away.

Think of how much moisture gets pulled up off of the Great Lakes during a lake effect snow event. Now think of a storm pulling air from an area potentially larger than one of the Great Lakes, that is FAR FAR warmer (in the 80's instead of the 40's) and concentrating all the moisture near an eye that is only 5-50 miles wide.


Thanks for a clear and easy to understand explanation. Thanks to you too, Weather456. There are so many facets to the development of systems, that one may often over-look the more subtle dynamics which go into land and sea systems. Interesting.
Member Since: July 17, 2009 Posts: 69 Comments: 25458
Quoting StormW:


Sitting close to the TUTT axis...in about 25 kts of shear.


What is a TUTT?
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308. Skyepony (Mod)
Quoting atmoaggie:

Thanks Skye.
I should have said specifically that I am wondering about the potential for a feedback from ENSO to the MJO, positive or negative.
Know of anything on that subject?


ENSO does effect MJO.. a sort of feedback.. I just can't remember exactly how, with certainty. May have a book around here...
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Quoting TheCaneWhisperer:


Wellington, FL


Wow! tha's brutal! need the fronts to start getting down here soon.
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AOI

AOI

AOI

AOI


And for those really bored.. the new Water Fall construction is underway on the Pond.
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Quoting Weather456:


Evaporation may seem small on the human scale but winds blowing over a large ocean and can make evaporation propagate. For example, one cell divides to 2, 4, 8, 26, 32, 64, etc to become a mass on larger scale that it is. One convection coming from the sea on scale of hundreds of km works in the same way.

Also positive feed back loop where the hurricane increases the rate of evaporation as it grows which in turn dry more winds and start the loop all over again but with increasing cycles.


Agreed.

Another important point is the simple, yet powerful effect of surface convergence. Air at the surface in a hurricane can be pulled in from many hundreds of miles away.

Think of how much moisture gets pulled up off of the Great Lakes during a lake effect snow event. Now think of a storm pulling air from an area potentially larger than one of the Great Lakes, that is FAR FAR warmer (in the 80's instead of the 40's) and concentrating all the moisture near an eye that is only 5-50 miles wide.
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Quoting tropicofcancer:


Where are you Cane?


Wellington, FL
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290. I don't know if you had a comment or picture for me. All I was able to see in your post was a quote of my post. If it was a picture, the corporate firewall probably ate it if it was shared from a personal storage website.
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301. Skyepony (Mod)
Quoting SCwannabe:
I'm just a lurker but it sure seems like x-Fred is flaring up quite a bit today! Any of the experts on here thinking their might be a chance of development? I see Dr. Master's doesn't think so. I was thinking about how fast TS Gaston-later Hurricane Gaston developed off of the SC coast a few years back.


There was a good quikscat pass of Fred-ex this morning.. Far from a closed circulation, no longer in the state of waiting for minimal decent conditions, he has a ways to go to be even a depression. Even if he stalled over the gulf stream some & land tightend him at landfall, Lack of MJO, just the suppressed tropical state of the world at the moment~ very small, outside chance of a minimal tropical storm landfalling at worse here. Not worth upsetting the markets over.
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Quoting StormW:
Good afternoon!

TROPICAL WEATHER SYNOPSIS SEPTEMBER 21, 2009 ISSUED 9:45 A.M. EDT


Thanks StormW. Any comment on the blob nearer the islands. Looks big, but no one is mentioning it. Probably not in a favorable environment.
Member Since: July 17, 2009 Posts: 69 Comments: 25458
Quoting TheCaneWhisperer:
A lot hotter than I thought it was going to be today in SCFL.

Heat Index: 108 °F


Where are you Cane?
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Quoting Skyepony:



A strong MJO in the spring, traveling across the pacific creates Westerly Wind bursts..aka west wind events.. These create the Kelvin waves that cause the onset of El Nino. As MJO events weaken with a 6-9 month lag so weakens El Nino.


Thanks Skye.
I should have said specifically that I am wondering about the potential for a feedback from ENSO to the MJO, positive or negative.
Know of anything on that subject?
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Can someone post the wind shear map...please! Thanks
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Quoting TheCaneWhisperer:


I agree fully. Only being able to comment on my local state, Florida, we're in deep doo-doo right now. Financially (Government, Private and Citizen's) and in the insurance markets. We're in no way done yet so the prayers continue. Not to mention the thousands of foreclosures that would need boarded up in the area. A strike wouldn't be pretty that's for sure.


I attended an open meeting of the Broward Emergency Management in early summer. One of the suggestions was to use the empty homes, condos, etc. as housing for the displaced in the event of a major disaster. Broward still has thousands of empty homes due to foreclosures as you know. Banks weren't too hot on the idea. Clean-up costs and insurance liability and the like.
Member Since: July 17, 2009 Posts: 69 Comments: 25458
A lot hotter than I thought it was going to be today in SCFL.

Heat Index: 108 °F
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Well Fred is loosing convection quickly, so do not worry press.
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Actually they are from Hurricaine Ivan.
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291. Skyepony (Mod)
Quoting atmoaggie:
I see the "master" has been about and laying our season and upcoming winter that the feet of El Nino as the primary factor.

I say, El What ?

1997:


2009:


How does ENSO relate to MJO?
(Really, I wish Michael StL were here, he would know. But, alas, his demeanor towards anyone that looked at his posts oddly got out of hand...or maybe he is here, but under another handle and exclusively talking tropics.)

MJO has been very good to us in the NW Atlantic except for that one spike when Ana, Bill, Claudette, and Danny formed:



A strong MJO in the spring, traveling across the pacific creates Westerly Wind bursts..aka west wind events.. These create the Kelvin waves that cause the onset of El Nino. As MJO events weaken with a 6-9 month lag so weakens El Nino.

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Quoting pearlandaggie:


Yeah, I know what you mean. Every couple of years we go to Fort Morgan, Alabama for vacation. We saw lots of dead pine trees last August when we were there. I suppose that these were from Katrina. Really sad to see all the dead trees....
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Quoting presslord:


me too...


Yeah... that was quite the little blow here in Mt.Pleasant,SC!
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Quoting SCwannabe:
I'm just a lurker but it sure seems like x-Fred is flaring up quite a bit today! Any of the experts on here thinking their might be a chance of development? I see Dr. Master's doesn't think so. I was thinking about how fast TS Gaston-later Hurricane Gaston developed off of the SC coast a few years back.


me too...
Member Since: August 13, 2007 Posts: 0 Comments: 10479
Quoting IKE:
Freddie is dead-ee....

TROPICAL WEATHER OUTLOOK
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
200 PM EDT MON SEP 21 2009

FOR THE NORTH ATLANTIC...CARIBBEAN SEA AND THE GULF OF MEXICO...

TROPICAL CYCLONE FORMATION IS NOT EXPECTED DURING THE NEXT 48 HOURS.

$$
FORECASTER PASCH


so certain are we!!
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Post (242) great Video LOL Cantore with hair and TWC actually giving a detailed update priceless
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Quoting bloodstar:
Things are getting really really bad in the Atlanta area.

how so?
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Quoting presslord:


lottsa dead, spindly trees..in fact, ya can see that in a number of places in and around that area...


Yeah, I know what you mean. Every couple of years we go to Fort Morgan, Alabama for vacation. We saw lots of dead pine trees last August when we were there. I suppose that these were from Katrina. Really sad to see all the dead trees....
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Quoting Weather456:
The 2009 Hurricane Season was also a blessing in disguise. My economy along with you guys in the USA is in downturn and a hurricane weaker than Georges would inflict twice the damage.



I agree fully. Only being able to comment on my local state, Florida, we're in deep doo-doo right now. Financially (Government, Private and Citizen's) and in the insurance markets. We're in no way done yet so the prayers continue. Not to mention the thousands of foreclosures that would need boarded up in the area. A strike wouldn't be pretty that's for sure.
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Quoting caneswatch:


Wow. That area is just practically asking for something. Weather, what do you think are the chances of a RI like Wilma with the water like that down in the Western Caribbean?


With Favorable wind shear and dry air, and proximity to land, it may not get to record numbers but it would easily turn into a major. Basically if this occurs during the upward, MJO in early Oct there may be trouble.
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Quoting hurricaneseason2006:
Weather456,

I have never seem to understand, how a hurricane uses evaporation on a scale that it is. I mean, evaporation seems like a slow and ineffective method and yet it can support storms like Wilma. Why is this so?


Evaporation may seem small on the human scale but winds blowing over a large ocean and can make evaporation propagate. For example, one cell divides to 2, 4, 8, 26, 32, 64, etc to become a mass on larger scale that it is. One convection coming from the sea on scale of hundreds of km works in the same way.

Also positive feed back loop where the hurricane increases the rate of evaporation as it grows which in turn dry more winds and start the loop all over again but with increasing cycles.
Member Since: Posts: Comments:

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