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 StormW:


One of the models, GFS I believe, does develop a ridge over the top of him, off the coast, and stalls him along the coast. Let's hope not.


That was the model to which I was referring. Didn't want to post it, lest I was bombaded with "Where is the post" The model does not show the direction to which it would be steered, though. After the stall, I mean. Any thoughts?
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Quoting JLPR:
Today is just a Rainy day in Eastern PR however 11years ago at this time Hurricane Georges was very close to making landfall on SE PR. So 11yrs ago on Sept 21 all hell was breaking loose in PR.



and since we are so lucky that has been the last hurricane to hit us directly, 11yrs and no hurricanes, that deserves a trophy =P we are a island sitting in the middle of the ocean on the Hurricane belt :) our hurricane shield is strong lol


Lol. Sssshhh! Knock on wood. We thought we were done after Rita. We don't tempt fate around here any more. ;)
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Quoting Grothar:
TO: td

:-)


TUTT? ;)
Member Since: June 28, 2006 Posts: 24 Comments: 8185
374. IKE
Nashville,TN. extended discussion...

"THE APPROACH OF A FRONT WILL MEAN INCREASING RAIN CHANCES AGAIN
INTO THE WEEKEND...BUT THIS FRONT WILL ALSO SIGNAL A CHANGE IN THE
LARGE SCALE PATTERN. BY NEXT MONDAY...NORTHWEST FLOW WILL DEVELOP
WITH DRY AND MUCH MORE FALL LIKE WX ACROSS THE AREA."....


Memphis,TN. extended...

"FRIDAY THROUGH MONDAY...MEDIUM RANGE MODELS SEEM TO BE IN DECENT
AGREEMENT WITH TRANSITIONING FROM A BLOCKING PATTERN TO A MORE
PROGRESSIVE PATTERN THIS WEEKEND. THE CLOSED LOW IS FORECAST TO
MOVE EAST FRIDAY AND SATURDAY AND DEVELOP INTO A FULL LATITUDE
TROF ACROSS THE EASTERN U.S. ON SUNDAY."

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Quoting NEwxguy:
wow,snow on the radar,and fall doesn't start until late tomorrow.


From NWS

1048 AM MDT MON SEP 21 2009

THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTHEAST AND NORTH CENTRAL
COLORADO.

.DAY ONE...TODAY AND TONIGHT

THE SEASONS FIRST WIDESPREAD SNOWFALL WILL OCCUR IN THE
MOUNTAINS...HIGH VALLEYS...AND MOST OF THE FRONT RANGE FOOTHILLS
TODAY. ACCUMULATIONS OF 1 TO 4 INCHES CAN BE EXPECTED...ABOVE 7500
FEET...SOME SLUSH CAN BE EXPECTED ON THE HIGHER MOUNTAIN ROADS
DURING PERIODS OF HEAVIER SNOWFALL.

ON THE PLAINS...RAIN SHOWERS WILL CONTINUE THROUGH THE MORNING AND
THEN DECREASE FROM NORTH TO SOUTH BY AFTERNOON. TEMPERATURES WILL
BE MUCH COLDER IN ALL AREAS. IT WILL BE COLD ENOUGH FOR A FEW
SNOWFLAKES IN AREAS SOUTH AND SOUTHEAST OF DENVER GENERALLY ABOVE
6000 FEET...BUT LITTLE OR NO ACCUMULATION IS EXPECTED IN THESE AREAS.
Member Since: June 28, 2006 Posts: 24 Comments: 8185
TO: td

:-)
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here is a zoom in of some first snow
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358, StormW.

Well, don't anybody worry much about Fred-ex. Tacoman has said that the season is over. He should know, he accurately guessed Katrina's track.

I know I feel safer...
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368. JLPR
Today is just a Rainy day in Eastern PR however 11years ago at this time Hurricane Georges was very close to making landfall on SE PR. So 11yrs ago on Sept 21 all hell was breaking loose in PR.



and since we are so lucky that has been the last hurricane to hit us directly, 11yrs and no hurricanes, that deserves a trophy =P we are a island sitting in the middle of the ocean on the Hurricane belt :) our hurricane shield is strong lol
Member Since: September 4, 2007 Posts: 36 Comments: 5223
Quoting IKE:
Check out the cold-air diving into the SE USA on the 12Z ECMWF...


I think our cold front is supposed to stall just north of us and dissipate into the weekend. And cause a lot of rain. Houston was the last hold out among the locals talking about the strong cold front. Now I think they're giving up too. Lol. I also noticed the lows in the GOM and BOC on that model too. Hope they stay that way. Just lows.
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wow,snow on the radar,and fall doesn't start until late tomorrow.
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Quoting bigblow:
I had a High School Classmate that lived on Isle Of Pines with her husband when Hugo hit. It made for an interesting story at our 25th reunion.


Isle of Palms...
Member Since: August 13, 2007 Posts: 0 Comments: 10458
I had a High School Classmate that lived on Isle Of Pines with her husband when Hugo hit. It made for an interesting story at our 25th reunion.
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first snow of season showing up on radar
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Quoting TheCaneWhisperer:


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.


Hey neighbor...I'm from down the road in western Lake Worth. It really is hot out there today. I hear what you are saying about the foreclosures and a hurricane strike. My neighborhood has a lot of foreclosures (including two on my street). I would be perfectly happy to see this season go by without a hurricane to worry about. Shuttering up my house would be work enough, let alone helping out with a foreclosed house!
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Quoting StormW:


The area should be almost in the Gulfstream.

Shear has been decreasing:



And the most recent updated shear forecast calls for shear to relax, albeit a small window, of which it didn't as of the 00Z and 06Z run:

GFS


CMC


StormW, is that a high trying to move above remnant Fred? If so, could it possible change the path of what is left?
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we are monitoring the Atlanta flooding situation for opportunities for Portlight to be of assistance...
Member Since: August 13, 2007 Posts: 0 Comments: 10458
Quoting presslord:
Floyd cost me a headsail...I like to at least remove all the canvass if it's gonna blow much...


yep...dem sails ain't cheap!
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Floyd cost me a headsail...I like to at least remove all the canvass if it's gonna blow much...
Member Since: August 13, 2007 Posts: 0 Comments: 10458
353. JLPR
remnants of 98L still spinning


and that's about it
Fred-Ex convection is dissipating and the blob close to the islands is under shear
this has been a very quiet peak =]
Member Since: September 4, 2007 Posts: 36 Comments: 5223
stormW.. if you would elaborate,, i always read your comments,,
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Quoting StormW:
What if I told you that Ghost of Fred may make a last ditch effort prior to coming ashore?


That Tampaspin took over your account?
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Quoting PcolaDan:


Thanks for that link.


no problem, I found it very interesting
Member Since: June 28, 2006 Posts: 24 Comments: 8185
Quoting StormW:
What if I told you that Ghost of Fred may make a last ditch effort prior to coming ashore?


I'd ask: When do I need to start buttoning up the boat?!?!?!?!?!
Member Since: August 13, 2007 Posts: 0 Comments: 10458
347. IKE
Check out the cold-air diving into the SE USA on the 12Z ECMWF...
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Quoting StormW:
What if I told you that Ghost of Fred may make a last ditch effort prior to coming ashore?



well J.B. forecast it to do that, I think
Member Since: June 28, 2006 Posts: 24 Comments: 8185
Quoting tornadodude:
Students Launch Camera to Edge of Space



Thanks for that link.
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Quoting Grothar:
School will be out soon! Everybody ready?


does that mean tacoman will be back from his "errands"?
Member Since: June 28, 2006 Posts: 24 Comments: 8185
Quoting Grothar:


Hey homeless, When did you sneak in? Lurking to see if everyone behaved themselves today. Big mess in Atlanta, huh. With all the gulleys they have, doesn't take much to flood some areas.


Hi Grothar. Yeah, it is sad about Atlanta. I had no idea. Too wrapped up in my own business to notice the rest of the world. :( I'll just be lurking/posting on and off today. Started the annual fall spring cleaning. Although it still feels like summer.
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FYI..the Ben Sawyer Bridge (pictured in Dr. Masters' blog entry) is still there and functional...one of only three draw bridges on the Intra Coastal Waterway in South Carolina...
Member Since: August 13, 2007 Posts: 0 Comments: 10458
School will be out soon! Everybody ready?
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Quoting SCwannabe:
Can someone post the wind shear map...please! Thanks


You're in Mt.P? I'm on Johns Island...
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Students Launch Camera to Edge of Space

Member Since: June 28, 2006 Posts: 24 Comments: 8185
Quoting homelesswanderer:
317. bloodstar

That is so sad. :(


Hey homeless, When did you sneak in? Lurking to see if everyone behaved themselves today. Big mess in Atlanta, huh. With all the gulleys they have, doesn't take much to flood some areas.
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New U tube at my blog here on the Super Typhoon, electrics and the QBO. Click my name methane mike to get there.
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STORM TOTATS FFC AREA

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333. LBAR
Nice NE "breeze" on a buoy 41 miles se of Charleston. Not sure if it's from FredEx, but...

Wind Direction Wind Direction (WDIR): NE ( 40 deg true )
Wind Speed Wind Speed (WSPD): 17.5 kts
Wind Gust Wind Gust (GST): 19.4 kts
Wave Height Wave Height (WVHT): 4.3 ft
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Quoting Grothar:


Didn't know you had to go to class. We all thought you went out for a taco!


haha yeah, no tacoman taco's for me :P
Member Since: June 28, 2006 Posts: 24 Comments: 8185
Quoting tornadodude:


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


Didn't know you had to go to class. We all thought you went out for a taco!
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Quoting homelesswanderer:
317. bloodstar

That is so sad. :(

yep. the woman was on the phone with 911 and dead in her van when they found her...a three year old missing when mobile home broke in half and floated away. back to work for me.
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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.
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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.