Isaac, once an unorganized and fast-moving storm, has slowed considerably and was plodding northwest at 8 mph by late Tuesday afternoon. Once it hits the coast, such a slow speed would be a cause for concern, because storms that travel at a leisurely pace tend to linger over flood-prone neighborhoods and dump large amounts of rain.
Forecasters are predicting 7 to 14 inches of rain once Isaac reaches land. Total rainfall could reach 20 inches in some isolated areas.
The National Hurricane Center said Isaac’s hurricane-force winds extend outward up to 60 miles. It issued a hurricane warning for the area east of Morgan City, La., to the Mississippi-Alabama border, including metropolitan New Orleans, Lake Ponchartrain and Lake Maurepas.”
The center said storm-surge flooding could reach depths of six to 12 feet if the peak surge occurs at high tide, and it warned that “tornadoes are possible along the northern Gulf Coast through tonight.”
In response, President Obama on Tuesday declared an emergency in Mississippi and ordered federal aid. Obama announced a state of emergency for Louisiana on Monday, making federal support available to save lives and protect public health and safety.
In a brief statement he delivered Tuesday morning at the White House, Obama said the federal government is ready to help and urged residents of the affected areas to take warnings seriously.
“As we prepare for Isaac to hit, I want to encourage local residents of the Gulf Coast to listen to your local officials and follow their directions, including if they tell you to evacuate,” he said. “We’re dealing with a big storm, and there could be significant flooding and other damage across a large area. Now’s not the time to tempt fate. Now’s not the time to dismiss official warnings. You need to take this seriously.”
Obama added: “The hardest work, of course, is still ahead. And as president, I’ll continue to make sure that the federal government is doing everything possible to help the American people prepare for, and recover from, this dangerous storm.
For all the focus on the wind strength of these storms, it is water that truly terrifies residents and officials.
“These water hazards — the storm surge and the inland flooding — are things that sometimes people forget,” National Hurricane Center Director Rick Knabb told reporters Monday. “They consider tropical storms and hurricanes as just windstorms, and they are far more than that.”