Name: Hurricanes
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<div class="rich-text">(This video is no longer available for streaming.) The city of New Orleans is cradled in swampland. To keep the water out, hundreds of miles of enormous levees and powerful pumps surround the city. But such a fortress is not invincible, and forecasters often have to make tough calls on pending storms. NOVA scienceNOW correspondent Peter Standring investigates what would happen if a hurricane hit New Orleans.
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Predicting a hurricane's intensity is difficult, but new tools may make it easier. 

<div class="rich-text">Predicting a hurricane's intensity is difficult, but new tools may make it easier. </div>

Predicting a hurricane's intensity is difficult, but new tools may make it easier.

Hurricanes

Planet Earth

<div class="rich-text"><h3>
 Hurricanes
</h3>

 PBS Airdate: January 25, 2005



 ROBERT KRULWICH
 
 : I wonder if I could have a hurricane, just a small
one please. Thank you.


 Now, the thing about hurricanes is, if there's one in the neighborhood and
you are, say, over here, the first thing you want to know is: "Is it coming at
me?" Because, if you're in its path, you're going to want to leave.


 Thank you.


 But over the years, scientists have gotten pretty good at predicting the
direction of a hurricanes but not so good at predicting a hurricane's
intensity.


 Hurricanes...I'll need one again.


 Hurricanes, because of changes in terrain and in water temperature, and all
kinds of things down below, can suddenly swell and then diminish and then swell
again. And because scientists don't have the tools to read hurricanes that
well, these changes are very, very hard to predict—until
recently...


 Thank you.


 ...'cause now there's a new development, a kind of CAT scan for
hurricanes.


 As our correspondent Peter Standring reports, predicting a hurricane's
power may now get a little easier.



 PETER STANDRING
 
 (scienceNOW Correspondent): When most
people think of New Orleans, they think of the French Quarter, Mardi Gras,
jazz, gumbo. But according to federal officials one of the most dire threats
facing the nation would be a massive hurricane striking New Orleans. They say
that if a major storm had a direct hit here, the effect would be devastating.
They're talking perhaps as many as 50,000 dead, up to a million homeless and a
city under water. And that disaster nearly happened this past hurricane season.


 When hurricane Ivan barreled into the Gulf of Mexico, it was on a collision
course with New Orleans, a city with a unique vulnerability to
hurricanes.



 RAY NAGIN
 
 (Mayor, New Orleans, Lousiana): This is a very
dangerous storm. Hurricane Ivan is approaching us.



 PETER STANDRING
 
 : Fearing the worst, the mayor called for an
evacuation of the city.



 MAN
 
 : 	I've been through a couple of hurricanes but this one looks like a
monster. I'm hoping it doesn't hit us directly.



 PETER STANDRING
 
 : Luckily for New Orleans, Ivan veered east at
the eleventh hour, and the Big Easy dodged a bullet.


 To get a sense of the damage a hurricane like Ivan would have caused if it
made a direct hit on the city of New Orleans, I met with emergency manager,
Walter Maestri.


 What have we got here?



 WALTER MAESTRI
 
 : Well, this is a surveyor's rod. And this can extend up
to 25 feet, and it shows us just how deep the water would be here if Ivan came
through.



 PETER STANDRING
 
 : And you're getting pretty high there,
Walter.



 WALTER MAESTRI
 
 : Notice we're probably about the second level, right?
There we go now. Watch. We're getting close. We're there.



 PETER STANDRING
 
 : What are we at?



 WALTER MAESTRI
 
 : Twenty two feet is what they tell us could be right here
in the French Quarter.



 PETER STANDRING
 
 : You're saying that this street, French
Quarter, under 22 feet of water?



 WALTER MAESTRI
 
 : If Ivan made that direct hit, this is what we'd be
looking at. We're swimming here. We're like fish, if we're alive.



 PETER STANDRING
 
 : Not good.



 WALTER MAESTRI
 
 : Not good.



 PETER STANDRING
 
 : Just 50 miles from Gulf of Mexico, New
Orleans is at such great risk because most of the city lies below sea level.
Settled in 1718, it's sandwiched between the Mississippi River and Lake
Pontchartrain.



 IVOR VAN HEERDEN
 
 (Louisiana State University): New Orleans was
built on a swamp. And in order to build it, they had to put a wall, a levee,
around the swamp, and then pump all the water out. As you pump the water out,
you allow oxygen to then get into the soils, the oxygen breaks down the organic
matter in the soils and they lose bulk and they sink.



 PETER STANDRING
 
 : To keep the river and lake from flooding this
ever-deepening bowl, which is more than 12 feet below sea level in some places,
hundreds of miles of giant levees like this one now surround New
Orleans.


 To get rid of rainwater that collects in the bowl, 22 pump stations were
installed throughout the city. These pumps are so powerful that they can suck
up 29 billion gallons of water a day from the city and push it all back into
the lake. Now, that's enough water to fill the stadium here in New Orleans, the
Superdome, in about 35 minutes.


 But in a strong hurricane, these pumps would be overwhelmed and the very
same levees that protect New Orleans from floods could be its demise.


 Hurricanes are whirling dynamos, generating enormous winds. These winds
create a gigantic swell of water called a storm surge. And in New Orleans, a
storm surge could deliver a fatal one-two punch.


 Approaching from the Gulf of Mexico, the storm surge would push water into
Lake Pontchartrain and up the Mississippi
River. As the water level rises, it would overflow the levees on the lake,
inundating the city from the north. A strong enough hurricane would push water
over the higher levees along the Mississippi River, flooding the city from the
south.


 In this doomsday scenario, levees intended to keep water out trap it inside
New Orleans.



 WALTER MAESTRI
 
 : If that bowl fills up, we have no way, necessarily, to
get that water out of here; in essence, Lake Pontchartrain, which surrounds us,
is transferred and becomes Lake New Orleans.



 PETER STANDRING
 
 : If anything, the situation is getting even
more dangerous. That's because wetlands that provide a natural defense against
storm surges are disappearing.


 To see how, University of New Orleans geologist Shea Penland takes me for a
swamp buggy ride into the bayous just a few miles south of the city. Here,
between New Orleans and the Gulf of Mexico, is the largest area of coastal
wetlands anywhere in the United States.


 So, Shea, why did we stop here?



 SHEA PENLAND
 
 (University of New Orleans): We stopped here because
this is an area that was solid land 50 years ago and today is open water.



 PETER STANDRING
 
 : Healthy wetlands weaken a hurricane by
starving it of warm ocean water, its fuel. But in the last 70 years, nearly
2,000 square miles of this protective buffer have eroded due to manmade and
natural causes.


 What does all this land loss mean to the city of New Orleans?



 SHEA PENLAND
 
 :	The wetlands are our natural speed bump; they're our first
line of defense. We have a slow disaster that's kind of eating its way towards
the city, and all of a sudden, here comes the hurricane. And that major
hurricane could be the one on the right track, the right trajectory that puts
the storm right down in the city, people can't get out, and we have the ten
thousand, twenty thousand, thirty thousand dead. And that's the worst case
scenario; that's what we're gambling with right now.



 PETER STANDRING
 
 : With so many lives at risk, accurately
predicting these killer storms is a high stakes endeavor.



 JEFFREY HALVERSON
 
 (NASA Goddard Space Flight Center): Forecasters
do walk a tightrope when they make forecasts for landfall. You don't want to
give people the wrong impression about every storm. You move them harmlessly
out of the way and nothing hits, it is a cry wolf kind of syndrome.



 PETER STANDRING
 
 : ...just what happened in the wake of
hurricane Ivan. With Ivan closing in on New Orleans, more than 600,000 people
evacuated the city. New Orleans shut down. The storm veered off course, but the question remains:
when another storm threatens the Louisiana coast, will people evacuate a second
time?


 In recent years, forecasting the track of a hurricane has improved
dramatically, but predicting its intensity, how strong it will be when it hits
land, is still a difficult challenge.



 MARSHALL SHEPHERD
 
 : If you just grab your glasses there and I'll give you
a test drive.



 PETER STANDRING
 
 : We're going to dive on into the storm?



 MARSHALL SHEPHERD
 
 : We are going to fly into the storm.



 PETER STANDRING
 
 : NASA is using satellites to understand
hurricanes both inside and out.



 MARSHALL SHEPHERD
 
 : Twenty, thirty years ago, when we used a conventional
view of a storm, we could really only see the cloud top. We could see how big
the storm was, we could see the white mass which represented the clouds, and
that was valuable, but that's all we could see. We were just touching the hood
of the car. Now we can pop the hood and look inside the storm.



 PETER STANDRING
 
 : To do that, they're using a satellite
equipped with weather radar, the only one of its kind.


 Much the way a CAT scan provides a three-dimensional picture of internal
organs, the satellite's radar is producing stunning pictures of a hurricane's
internal structure. And these unique images reveal something unexpected:
extremely violent thunderstorms, called hot towers—seen here in red.
These storms-within-a-storm can reach more than 10 miles into the sky.



 MARSHALL SHEPHERD:
 
 When we see these hot towers, we think that they are
giving us a clue that the storm is releasing a lot of energy, and it's firing
on all cylinders if you will. And that may be a sign that the storm is about to
undergo intensification processes.



 PETER STANDRING
 
 : So you do think, preliminarily, that there's
a link between the abundance of hot towers, and how strong and intense a storm
is going to be?



 MARSHALL SHEPHERD
 
 : That's exactly where we are in the research. We don't
have enough evidence to conclusively link the number of hot towers or how tall
they are to intensity, but our hypothesis is that they might be a sign or a
clue that this hurricane is about to enter an intensification phase.



 PETER STANDRING
 
 : And if this work pays off, forecasters will
be able to predict more accurately not just where a storm will hit, but whether
it will weaken or intensify just before landfall.



 WALTER MAESTRI
 
 : What really scares me to death is that we get a category
2 or 3 hurricane that rapidly intensifies to a category 4 or 5 storm. That's
the one that could absolutely be catastrophic here because we wouldn't get
people out. People wouldn't be moving early as they were for Ivan. They would
all be here, in the community, and all of a sudden we'd get this wall, this
massive wall of water, the double whammy.



 IVOR VAN HEERDEN
 
 : Every year that goes by, the probability of this
killer storm occurring increases.



 JEFF HALVERSON
 
 : It's inevitable that at some point, probably in the next
10 to 15 years, there's going to be a tragedy somewhere along the U.S.
coastline. It may not be New Orleans... some other high population center
 
 .
 
 Fairly likely scenario.



 PETER STANDRING
 
 : Gaining a deeper understanding of hurricanes
is the best answer, but it won't happen overnight.


 Here on Bourbon Street, the good times continue to roll. But the party
atmosphere masks a widespread concern about the threat of these killer storms.
For this city, or any other place that's at risk, improvements in hurricane
prediction can't come soon enough.



 ROBERT KRULWICH
 
 : Correspondent Peter Standring.
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