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 JLPR:
Fred-Ex convection isn't that impressive

but the Gulf Stream is close so lets not discount it yet :)


As I mentioned earlier, it just started to blow up, next frame will probably show the convection a bit deeper.
Member Since: July 1, 2008 Posts: 13 Comments: 7423
Quoting JLPR:
Fred-Ex convection isn't that impressive

but the Gulf Stream is close so lets not discount it yet :)


oh wait your nuts if you hadn't discounted it yet lol.
I expect little from Fred as he heads into the GA/SC area over the upcoming week. Warm ssts yes but unfavorable upper winds forecasted to impact Fred which should moderate development.

Also I have seen the sat images of Fred and I wouldnt call that a comeback.
Member Since: July 24, 2005 Posts: 407 Comments: 19076
525. JLPR
Fred-Ex convection isn't that impressive

but the Gulf Stream is close so lets not discount it yet :)
Member Since: September 4, 2007 Posts: 36 Comments: 5223
Quoting iceman55:
tornadodude .more rain coming this way.


yeah, you dont need anymore rain
Member Since: June 28, 2006 Posts: 25 Comments: 8360
Interesting to see the topographically enhanced snow/ice mix over the CO Rockies.... I would love to head out there for the fall colour, but I don't want that to be white because of a snow fall..... lol
Member Since: October 25, 2005 Posts: 19 Comments: 22594
522. Relix
Quoting JLPR:
98L looking a little interesting =P
The LLC is a little to the SW of the convection
(under the weaker convection)close to 15N 47.5W


Meeh, too far north to bring more rains to PR =P
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Quoting Hurricane009:
snow in colorado!!!!!!!!


I see that lol I also commented on your blog
Member Since: June 28, 2006 Posts: 25 Comments: 8360
Quoting TexasHurricane:


Hi Homeless..... I see things are still quiet.


Hi Tex. Sorry for the delayed response. Crazy day. You've got mail. Be back on later. Have a good evening. :)
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This ramp up is different then the other false alarms. Banding is evident, convection is near the center, shear is 5-10 knots. Something to watch tonight, waiting on Quickscat.
Member Since: July 1, 2008 Posts: 13 Comments: 7423
TampaSpin,

Been tracking that feature over the past few days and it is the remnants of the upper low over the NE Caribbean about a week ago.
Member Since: July 24, 2005 Posts: 407 Comments: 19076
Quoting iceman55:
tornadodude .yeah. rain here now street flood haha .


be safe lol yeah, looks like that rain over Missouri is headed my way :)
Member Since: June 28, 2006 Posts: 25 Comments: 8360
Quoting hunkerdown:
Come on, you know Reed "long island express" Zone has a better handle at predicting truth here...


you most obviously missed StormW hinting at Ex Fred possibly getting going if it stalls in the Gulf Stream. He also pointed out before he left earlier that the MLC with all the convection is possibly working to the surface

So lets not pretend Reed is the only one who is looking at Ex Fred still.
511. JLPR
98L looking a little interesting =P
The LLC is a little to the SW of the convection
(under the weaker convection)close to 15N 47.5W
Member Since: September 4, 2007 Posts: 36 Comments: 5223
Quoting TampaSpin:
xFred is looking better than he has in 5 days...but, he has no closed LLC. The area to watch will be in the BOC as i have been saying the past few days. The MidLevel spin it about to exit the Yucatan.



Hi Tampa - What are you thinking it may do?
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Quoting iceman55:





pretty stormy isnt it?
Member Since: June 28, 2006 Posts: 25 Comments: 8360
Quoting IKE:
Apparently the NHC isn't impressed...

TROPICAL WEATHER OUTLOOK
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
800 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 KIMBERLAIN



It just started to ramp up, like 30 minutes ago. Persistence is the key, 2 a.m. could either be nothing if this is another freddy joke, or something if it actually gets going. Shear is 5-10 knots, but again, persistence is the key. Also waiting for the quickscat to see if it picks up what I see, might just be my eyes.
Member Since: July 1, 2008 Posts: 13 Comments: 7423
Quoting IKE:
Apparently the NHC isn't impressed...

TROPICAL WEATHER OUTLOOK
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
800 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 KIMBERLAIN

Come on, you know Reed "long island express" Zone has a better handle at predicting truth here...
Member Since: Posts: Comments:
xFred is looking better than he has in 5 days...but, he has no closed LLC. The area to watch will be in the BOC as i have been saying the past few days. The MidLevel spin it about to exit the Yucatan.

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Question is.. 07L lost it's LLC, will this be re-designated as 07L, or 99L?
Member Since: July 1, 2008 Posts: 13 Comments: 7423
501. IKE
Apparently the NHC isn't impressed...

TROPICAL WEATHER OUTLOOK
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
800 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 KIMBERLAIN

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Quoting Chicklit:
Interesting point Dr. Masters made in his blog today about The Keys being susceptible to surge.
have you ever seen the high water mark in the Whale Harbor "lighthouse" (in Islamorada) ? Storm surge in the Keys is no secret.
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Quoting iceman55:
reedzone hey


Hi Iceman, 07L looks to be organizing in favorable conditions tonight for the first time in a week.
Member Since: July 1, 2008 Posts: 13 Comments: 7423
Quoting Ameister12:

Double 07L has not look this good in a while!


Here's what bumping the chances, even though 07L had good blow ups of convection in the past, banding was not all that good and convection was blown away. This time, we have very structural banding with a ball of convection close to a possible LLC. Quickscat will determine this, hopefully it doesn't miss it.
Member Since: July 1, 2008 Posts: 13 Comments: 7423
Quoting Chicklit:
FredEx not looking well tonight.

He looked well near CV island after that only burst of convection every now and then.
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07L by the way is also in 5-10 knots of shear, probably why outflow has improved and convection is popping.

Member Since: July 1, 2008 Posts: 13 Comments: 7423
Quoting reedzone:
Wow, I'm impressed, literally. 07L "looks" like it's blowing new convection near a possible developing LLC, good banding. Shear also dropped in this area, could *Double 07L* give us a morning surprise? Stay tuned.

07L

Double 07L has not look this good in a while!
Member Since: August 9, 2009 Posts: 10 Comments: 5077
Quoting reedzone:
Wow, I'm impressed, literally. 07L "looks" like it's blowing new convection near a possible developing LLC, good banding. Shear also dropped in this area, could *Double 07L* give us a morning surprise? Stay tuned.

07L

The apperance of Fred tells me the shear has really dropped now and a small anticyclone is set to build in over him until landfall. Could get interesting.
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CaribbeanLoop
If it's getting into the Caribbean, it's got to start in the Caribbean, imo.

shearmap
Off to do homework; see y'all later.
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The quickscat will be quite interesting with the remnants o Fred tonight, it appears by looking at the satellite, a tight circulation has formed with a burst of convection.
Member Since: July 1, 2008 Posts: 13 Comments: 7423
Good evening!
Member Since: August 9, 2009 Posts: 10 Comments: 5077
Wow, I'm impressed, literally. 07L "looks" like it's blowing new convection near a possible developing LLC, good banding. Shear also dropped in this area, could *Double 07L* give us a morning surprise? Stay tuned.

07L
Member Since: July 1, 2008 Posts: 13 Comments: 7423
Fred is actually looking better. His overall structure has improved and is showing some signs of banding. convection has been on the increase as well over the last hour.
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Quoting iceman55:
hmmmm


I swear man.. buy a Vowel before you guess at what to type.

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Quoting PensacolaDoug:
I started snow skiiing 8 yeas ago when I was 42. Iv'e been on 9 ski trips, all but one to Summit County. The other was to Vail in Eagle County about another 20 miles or so west of Copper Mountain.
You're in the right spot then/ an awesome area ski area is Summit County?
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Rain?
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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.

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