Early Thursday, the storm was thrashing the Bahamas with widespread damage reported on at least two southern islands. It was a powerful Category 3 hurricane with winds at 115 mph. Forecasters said the winds will ramp up quickly over the next day and Irene was expected to blow into a monstrous Category 4 with winds at least 131 mph.
From North Carolina islands connected to the mainland by just a handful of bridges to the waterlogged shores of New England, officials are calculating what they need to do if Irene becomes the first major hurricane to strike the East Coast in seven years.
They're scrambling to inspect bridges, dusting off evacuation plans and getting sandbags ready for potential floods. And considering where and when to move people out of harm's way.
"You have to recognize that you're living here on an island, and island living represents certain risks," said Edward Mangano, county executive in Long Island's Nassau County, where school buses were being moved to higher ground in case they're needed to evacuate residents to storm shelters. "And those risks appear now, at least, to be tracking toward us."
Irene could hit North Carolina's Outer Banks on Saturday afternoon with winds around 115 mph (185 kph). It's predicted to chug up the East Coast, dumping rain from Virginia to New York City before a much-weakened form reaches land in Connecticut. Finally, it should peter out in Maine by Monday afternoon.
A hurricane watch was issued early Thursday for much of the North Carolina coast including the Outer Banks. A hurricane watch means hurricane conditions are possible within 36 hours. Also, a tropical storm watch was issued for much of South Carolina's coast.
Even without hurricane-force winds, northeastern states already drenched from a rainy August could see flooding and fallen trees.
"You want to go into a hurricane threat with dry soil, low rivers, a half moon," New Jersey state climatologist David Robinson said.
That is not the case. The Garden State has gotten twice as much rain this month as in a normal August, and high tide happens at 8 a.m. EDT on Sunday, when Irene might be passing by.
While the storm's path isn't definite, officials are taking nothing for granted.
In Maryland, inspections of bridges looking for cracks in the support piers and other structural features found no damage, according to state transportation agency spokeswoman Teri Moss. In Virginia, with a southeastern corner that could be in Irene's way, cities along the coast are reviewing their evacuation plans, said Laura Southard, spokeswoman for the state Department of Emergency Management.
"If there is an evacuation, people don't have to go to Richmond or Williamsburg," she said. "They just have to get to higher ground. There are multiple routes out. Cities and localities work hard year-round on their plans."
North Carolina's Outer Banks, which look the likeliest to get a serious hit from Irene, have a long history of hurricanes, and building codes and emergency plans reflect that. Structures in the region are designed to withstand up to 110 mph sustained winds and gusts of up to 130 mph for three minutes. Evacuation routes are meticulously planned, down to the order in which counties hit the road.
Ocracoke Island, a tiny Outer Banks community, has already ordered visitors off, but it has special challenges since it's only accessible to the mainland by boat. Dare County ordered evacuations to start Thursday and Currituck County was weighing its decision.
Some of the region's most popular destinations rely on the ailing Bonner Bridge, which was built in 1963 and intended to last 30 years, to connect Hatteras Island to the northern Outer Banks. There's no other way to reach Hatteras except by boat.
The bridge handles about 2 million cars a year and the state DOT ranks it a 2 on its safety meter, with 100 being the highest, or most safe, designation.
"We're going to shift people and resources around to do what we need to do and keep the roads open," said North Carolina Department of Transportation spokeswoman Nicole Meister. The 2.7-mile bridge won't stay open if it's deemed unsafe - which happened during Hurricane Earl last year - but the state has an emergency ferry terminal ready in that case to get people off the island, Meister said.
Farther north, precautions so far were mainly wait-and-see as officials watched for developments in the forecast.
New York City officials had begun preparations to evacuate residents from low-lying areas of the city if necessary. The city's subway stations and tunnels would likely be flooded in places, and officials plan to shut the system down ahead of time to reduce damage to the infrastructure.
"The sense is that we're going to be facing a strong tropical storm" with winds of 40 to 60 mph, said Office of Emergency Management Commissioner Joseph F. Bruno.
But Bruno added that the city's agencies were preparing for a Category 1 hurricane with winds surpassing 74 mph and waters surging dangerously in low-lying areas. With five hospitals and nursing homes in the area, officials were readying to possibly evacuate the most frail and needy.
Roads and bridges in Massachusetts are likely to bear the weather in good condition, said Peter Judge, a spokesman for the Massachusetts Emergency Management Agency. But the agency is planning for flooding and is keeping an eye on the 3,000 public and private dams throughout the state.
The Office of Dam Safety regulates about half the dams in Massachusetts and earlier this year a state audit rated 100 of those owned by 62 cities and towns as unsafe or in poor condition.
For longtime residents of the Outer Banks, getting off the island isn't always the biggest problem.
"The problem is getting back on," said Mary Morgan, who works at the Lighthouse View Motel in Buxton.
Inland flooding can close roads for days in severe situations, making it impossible to get back on the island until the water level falls. That makes people who live here far more reluctant to leave than tourists visiting for a week.
"I am prepared to evacuate," said Jen Ray, owner of The Space Between, a boutique and espresso bar in Frisco. "I'm not sure I'm going to."
This program aired on August 25, 2011. The audio for this program is not available.