- NEW: As of 11 a.m. ET, Irene was moving over crooked and Acklins islands, the NHC says
- NEW: parts of northern Haiti are flooded, the U.N. says
- NEW: "We must all prepare for the worst," the North Carolina governor says
- NEW: some Outer Banks residents were planning "hurricane parties," a CNN iReporter say
Read more about Hurricane Irene from CNN affiliate WSAV.
Miami (CNN) — Hurricane Irene intensified into a Category 3 storm Wednesday, threatening much of the United States’ East Coast in the coming days.
The storm had maximum sustained winds of 115 mph, and is expected to strengthen further "in the next day or so," the National Hurricane Center said Wednesday morning.
"this is a huge storm," said CNN Meteorologist Jacqui Jeras. "the cloud field is more than 800 miles across. the tropical storm force winds extend out 200 miles from the center."
The storm could threaten large sections of the Eastern Seaboard, from the Carolinas northward through the northeast.
The strengthening, which officially made Irene a major hurricane, came as the storm continued to pound the southeastern Bahamas and the Turks and Caicos Islands.
At 11 a.m. ET, Irene was turning northwestward, with its eye moving over crooked and Acklins islands, the National Hurricane Center said.
"On the forecast track, the core of Irene will move across the southeastern and central Bahamas through tonight and over the northwestern Bahamas on Thursday," the Hurricane Center said.
Gallery: Hurricane Irene intensifies Irene reaches Category 3 near Bahamas Florida prepares for Irene Irene strikes Turks and Caicos
In Nassau, many people had evacuated by Wednesday morning. Shopkeepers were boarding up their storefronts, and residents prepared to hunker down for the storm’s arrival.
"We’ve been through quite a few hurricane so were pretty much prepared," said Brian Nottage, who owns a shop and ice cream parlor in downtown Nassau.
Irene’s path will see it rake a large portion of the island chain as it heads northwest toward the United States.
The storm unleashed heavy rains across northern Haiti, causing flooding, the United Nations said Wednesday. there were no reports of major losses or damage, U.N. officials said.
Most of the latest forecasts suggest the storm will avoid landfall in North Carolina. "however, this is a very dangerous storm and much of the East Coast, including North Carolina, should be prepared for a landfall," said Jeras.
Some computer models suggest new York or new Jersey could be hit.
"Everywhere from North Carolina to Massachusetts remains in the cone of uncertainty," said Jeras. "worst case scenario, we could be looking at two landfalls, or we could be lucky and get a brush instead of a direct hit… Even if Irene doesn’t make landfall in the United States, it may very well bring flooding rains, damaging winds and power outages to the Northeast. planning is critical and everyone needs to be ready with a disaster plan and a safety kit."
Hyde County, in North Carolina’s Outer Banks, declared a state of emergency for Ocracoke island and the county’s mainland beginning at 5 a.m. Wednesday — along with a mandatory evacuation for all visitors and a voluntary evacuation for residents. the mandatory evacuation will extend to residents beginning 5 a.m. Thursday, Hyde County Emergency Services said.
Ocracoke is reachable only by boat or private plane.
While forecasts showed the storm "moving further from the coast and toward the sea," North Carolina Gov. Beverly Perdue said Wednesday, "we must all prepare for the worst."
In Kill Devil Hills in the Outer Banks, locals who insist on staying trough the storm were planning "hurricane parties" as they stocked up on water, canned food, and flashlight batteries, said CNN iReporter Penelope Penn, who was in the area Tuesday. "the water was so calm and the sky so clear at the outer banks last night. It truly is calmest before a storm," she added. On Wednesday, Penn was in nearby Virginia Beach.
Inland, Lila Little of Chapel Hill, North Carolina, told CNN, "We are a bit nervous, since hurricanes are so unpredictable, but we have been here many times before." Little has lived in the area for more than 20 years.
"the economic effect will be the worst I think — Labor Day weekend will be a bust for the beaches here, and they count on that last bit of revenue before the season ends," she said.
The last major hurricane to strike the United States was Wilma in 2005, which was a Category 3 at landfall, said Jeras. Hurricane Katrina, earlier the same year, was also a Category 3 at landfall.
The most recent hurricane to make landfall in the United States was Ike in 2008, which hit near Galveston as a Category 2.
Hurricane Floyd in 1999 was the most recent major hurricane to hit North Carolina’s Outer Banks. It was a Category 2 at landfall.
Hurricane Gloria in 1985 was the most recent hurricane to hit new York. it was a Category 3 at landfall, the National Hurricane Center said. in 1991, Hurricane Bob hit Massachusetts, a Category 2 at landfall.
If a Category 3 hurricane makes landfall, "devastating damage will occur," according to the National Hurricane Center’s Saffir-Simpson scale. "there is a high risk of injury or death to people, livestock, and pets due to flying and falling debris." Older mobile homes will be destroyed, and newer ones could be as well. "Well-built frame homes can experience major damage involving the removal of roof decking and gable ends," the Hurricane Center explained.
"Numerous windows will be blown out of high-rise buildings resulting in falling glass, which will pose a threat for days to weeks after the storm. most commercial signage, fences, and canopies will be destroyed. many trees will be snapped or uprooted, blocking numerous roads. Electricity and water will be unavailable for several days to a few weeks after the storm passes."
Hurricane Ivan in 2004 "brought Category 3 winds and impacts to coastal portions of Gulf Shores, Alabama," the Hurricane Center said.
Bill Read, director of the Hurricane Center, said Irene could cause problems with flooding in northeastern states that have already experienced high levels of rainfall this summer.
He said the Atlantic Ocean up to Cape Hatteras in North Carolina is warm enough to sustain a major hurricane.
"all East Coast residents should pay close attention to this storm and take the time now to prepare," Craig Fugate, the Federal Emergency Management Agency administrator, said Tuesday.
"People think hurricanes are a Southern thing but people in the mid-Atlantic and Northeast need to take Irene seriously," Fugate said. "We have a lot of time for people to get ready but we don’t have forever."
The Hurricane Center’s five-day forecast map shows the storm approaching North Carolina on Saturday and hugging the coast throughout the weekend.
Widespread damage is possible from the coastal Carolinas all the way up to the Canadian Maritimes, including the major cities of the Northeast, CNN Meteorologist Dave Hennen said.
Irene is expected to pass well east of Florida so only minimal effects are expected Thursday and Friday as the storm moves northward toward the Carolinas.
"We will be ready if Hurricane Irene reaches North Carolina," Gov. Beverly Perdue said Tuesday. "Our teams are already lining up supplies, trucks and resources to reach anywhere the storm might touch."
In South Carolina, emergency officials in Beaufort County, which includes Hilton Head Island, worked to make certain that construction sites on major highways could be cleared quickly in case evacuations of coastal areas became necessary.
"We’re contacting (construction crews) every day now to make sure if we should have to do something, that they could remove their barrels and construction equipment, etc. to clear the road so we don’t have impediment in the roadways," county Emergency Management Director Todd Ferguson told CNN affiliate WSAV TV Tuesday. "We … will continue to do that until this threat is passed."
In Puerto Rico, officials reported the death of a 62-year-old woman Tuesday as drenching rains from Irene soaked the U.S. commonwealth. she was trying to cross a bridge in a car over a flooded creek when the vehicle was inundated and she drowned, according to Lourdes Vazquez, a spokeswoman for the city of Carolina.
The storm left widespread damage on the island, leaving about 600,000 electric customers without power at its peak.
President Barack Obama has signed an emergency declaration for Puerto Rico, providing for federal disaster assistance.
CNN’s Ed Payne, Josh Levs, and Nelson Quinones contributed to this report.