* Landfall expected within hour
* Obama warns of "significant flooding and other damage"
* Massive new floodgate part of city's beefed-up defenses
* Nearly all Gulf of Mexico oil production halted
By Scott Malone and Kathy Finn
NEW ORLEANS, Aug 28 Hurricane Isaac gathered
strength as it bore down on New Orleans on Tuesday, bringing
high winds and soaking rains that will pose the first major test
to the city's multibillion-dollar flood protections, seven years
after Katrina devastated the U.S. Gulf Coast.
Hundreds of U.S. Army National Guard troops took up
strategic positions around New Orleans, preparation meant to
avoid the chaos seen in the days and weeks after Katrina in
Isaac's storm surge poses a major test of the so-called
Crescent City's new flood-control systems and reinforced levees
that failed in 2005, leaving parts of the city underwater.
Forecasts from the U.S. National Hurricane Center showed the
storm coming ashore in the Mississippi Delta late on Tuesday,
possibly taking direct aim at New Orleans.
"Many parts of the state could see 24 to 38 hours of
tropical storm-force winds," Louisiana Governor Bobby Jindal
told a news conference. "We're going to see a lot of downed
trees and power lines," he said. "We need people to stay safe."
Brandishing automatic assault rifles to ward off any threat
of looting, the troops in military vehicles took up positions on
mostly deserted streets. Their arrival came as driving rain and
stiff winds battered the city's famous tourist district, The
French Quarter, and its boarded-up storefronts. White-capped
waves formed in Lake Pontchartrain.
Earlier, the Army Corps of Engineers closed for the first
time the massive new floodgate on the largest storm-surge
barrier in the world, at Lake Borgne, east of New Orleans.
In other preparations, oil production in the U.S. Gulf of
Mexico nearly ground to a halt, and ports and coastal refineries
curtailed operations as Isaac neared.
At 5 p.m. CDT (2200 GMT), the Hurricane Center said Isaac
was centered about 105 miles (170 km) southeast of New Orleans
with top sustained winds of 80 miles per hour (130 kph).
The storm, becoming better organized as it nears land, was
traveling at a relatively slow 8 mph (13 kph). That pace is a
concern for people in its path since slow-moving cyclones can
bring higher rainfall totals.
Isaac was about 370 miles (595 km) wide and due to make
landfall at the mouth of the Mississippi River within the hour.
Heavy rains and big storm surges were also forecast for
parts of Mississippi, Alabama and the Florida Panhandle.
Isaac spared Tampa, Florida, where the Republican National
Convention began on Monday. But it forced party leaders to
revamp their schedule. They may have to make further revisions
so as not to be seen celebrating Mitt Romney's presidential
nomination while Gulf Coast residents struggle through the
President Barack Obama urged Gulf Coast residents to take
cover and heed warning, saying, Now was "not the time to tempt
fate." He issued emergency declarations for
Louisiana and Mississippi earlier this week because of Isaac.
Isaac had New Orleans in its sights as the city is still
recovering from Katrina, which swept across it on Aug. 29, 2005,
killing more than 1,800 people and causing billions of dollars
After Katrina, the Corps of Engineers built a $14.5 billion
flood defense system of walls, floodgates, levees and pumps
designed to protect the city against a massive tidal surge like
the one that swamped New Orleans in Katrina's wake.
The floodgate that closed on Tuesday is 26 feet (8 meters)
high and 1.8 miles (2.9 km) long. It was designed to prevent the
Industrial Canal from breaching its walls, as it did in 2005,
inundating the Lower Ninth Ward, Gentilly and New Orleans East
neighborhoods, and St. Bernard Parish.
Most of the Lower Ninth, still scarred by the devastation of
Katrina, was deserted on Tuesday. Residents who hadn't evacuated
were unloading water, food and fuel from their cars and trucks
to take into their homes.
"We've got all kinds of eats and treats," Arthur Anderson,
61, who was trapped in the attic of his house during Katrina
before he escaped by boat.
Authorities have urged thousands of residents in low-lying
areas to leave, warning that the storm could flood towns and
cities in Mississippi and Alabama, as well as Louisiana, with a
storm surge of up to 12 feet (3.7 meters).
Rainfall accumulations, potentially totaling as much as 20
inches (50 cm) in some areas, could also trigger widespread
flooding. Customers in Louisiana's coastal parishes were already
Isaac was not forecast to strengthen beyond a Category 1
hurricane, the lowest on the five-step Saffir-Simpson scale. Its
top projected winds were about 80 mph (129 kph). While that
would be well below the intensity of Katrina, which was a
Category 3 storm, the size of Isaac's slow-moving system has
forecasters predicting widespread flooding.
"It's going to take till the weekend before this gets out of
the southeastern states," Hurricane Center Director Rick Knabb
told reporters on a conference call Tuesday afternoon.
In the French Quarter, most businesses were closed and
boarded up on Tuesday, while a handful of workers piled sandbags
along doorways. Police and military vehicles were parked
throughout the neighborhood.
One tourist left in the district was Craig Drees, an
accountant from Russells Point, Ohio.
"It's a little eerie how quiet it is," said Drees, standing
on a street corner with a few friends. "But it seems like the
city is taking this very seriously and will be working to keep
U.S. ENERGY OUTPUT DISRUPTED
With more than 90 percent of offshore U.S. Gulf of Mexico
oil production shut in and nearly half of natural gas output
offline, energy companies along the Gulf Coast refining center
braced for the storm's impact, shuttering some plants and
running others at reduced rates ahead of Isaac's landfall.
Intense hurricanes such as Katrina -- which took out 4.5
million barrels per day of refining capacity at one point --
have flooded refineries, keeping them closed for extended
periods and reducing fuel supplies.
The U.S. Department of Energy estimated that about 12
percent of the Gulf Coast's refining capacity had gone offline.
Louisiana usually processes more than 3 million barrels per day
of crude into products like gasoline.
Although no damage to offshore installation had been
reported, some energy experts said the sweeping disruption of
oil production, refineries and key import terminals could make
it more likely the U.S. government would release oil supplies
from its nearly 696-million-barrel Strategic Petroleum Reserve.
A release, which had previously been under consideration, is
still on the table, White House spokesman Jay Carney told
reporters on Tuesday.
Even with Isaac's disruptions to production, international
benchmark Brent crude traded down slightly to $112 a barrel on
Isaac killed at least 23 people and caused significant
flooding and damage in Haiti and the Dominican Republic before
skirting the southern tip of Florida on Sunday.