The MTA has never before halted its entire system — which carries about 5 million passengers on an average weekday — in advance of a storm, though the system was seriously hobbled by an August 2007 rainstorm that disabled or delayed every one of the city's subway lines.
Readers capture Hurricane Irene's approachOn Thursday, Bloomberg ordered nursing homes and five hospitals in low-lying areas evacuated beginning Friday and advised residents on the southern tip of Manhattan and on Brooklyn's Coney Island to start moving items upstairs.
"We do not have the manpower to go door-to-door and drag people out of their homes," he said. "Nobody's going to get fined. Nobody's going to go to jail. But if you don't follow this, people might die."
Apartment building managers emailed residents, telling them to close windows and expect power outages. Flyers were posted in building lobbies.
Forecasters said Irene passing near Manhattan could lead to a nightmare scenario: shattered glass falling from skyscrapers, flooded subways and seawater coursing through the streets.
Even if the winds aren't strong enough to damage buildings in a metropolis made largely of brick, concrete and steel, a lot of New York's subway system and other infrastructure is underground and subject to flooding in the event of an unusually strong storm surge or heavy rains.
Slideshow: Cartoonists poke at Irene (on this page)New York City's two airports also are close to the water and could be inundated, as could densely packed neighborhoods, if the storm pushes ocean water into the city's waterways.
In the low-lying Financial District surrounding Wall Street, the New York Fed was readying contingency plans but expected normal functioning of its open market operations on Monday, a spokesman said.
The city had a brush with a tropical storm, Hanna, in 2008 that dumped 3 inches of rain in Manhattan.
In the last 200 years, New York has seen only a few significant hurricanes. In 1821, a hurricane raised tides by 13 feet in an hour and flooded all of Manhattan south of Canal Street, the southernmost tip of the city. The area now includes Wall Street and the World Trade Center memorial.
Readers capture Hurricane Irene's approachNorth CarolinaTraffic was steady as people left the Outer Banks. Tourists were ordered to leave the barrier islands Thursday, though local officials estimated Friday that about half the residents on two of the islands have ignored evacuation orders.
As a result, officials ordered dozens of body bags.
"I anticipate we're going to have people floating on the streets, and I don't want to leave them lying there," said Richard Marlin, fire chief for one of the seven villages on Hatteras. "The Coast Guard will either be pulling people off their roofs like in Katrina or we'll be scraping them out of their yards."
In Nags Head, police officer Edward Mann cruised the streets in search of cars in driveways — a telltale sign some planned to stay behind. He warned those that authorities wouldn't be able to help holdouts, and that electricity and water could be out for days.
Price gougers put on noticeSome told Mann they're staying because they feel safe or because the storm won't be as bad as predicted. Mann, 25, said some have told him they've ridden out more storms than years he's been alive.
Bucky Domanski, 71, was among those who told Mann he wasn't leaving. The officer handed the retired salesman a piece of paper warning of the perils of staying behind. Domanski said he understood.
"I could be wrong, but everything meteorologists have predicted never pans out," Domanski said. "I don't know, maybe I've been lulled to sleep. But my gut tells me it's not going to be as bad as predicted. I hope I'm right."
Video: N.C. Gov.: Preparing for worst, praying for best As thousands fled beach towns, some farmers began early harvests to minimize any losses to Irene.
VirginiaAfter the Outer Banks, the next target for Irene was the Hampton Roads region of southeast Virginia, a jagged network of inlets and rivers that floods easily. Emergency officials have said the region is more threatened by storm surge, the high waves that accompany a storm, than wind.
Gas stations there were low on fuel Friday, and grocery stores scrambled to keep water and bread on the shelves.
Few people were left along the coast of Virginia Beach, where officials ordered the mandatory evacuation of the city's Sandbridge section.
Similar orders were issued for at least 10 other localities and some roads inland had backups 7-8 miles long.
MarylandThe beach community of Ocean City was taking no chances, ordering thousands of people to leave.
"This is not a time to get out the camera and sit on the beach and take pictures of the waves," said Gov. Martin O'Malley.
Washington, D.C.Irene forced the postponement of Sunday's planned dedication of the Martin Luther King Jr. Memorial on the National Mall. While a direct strike on the nation's capital appeared slim, organizers said the forecasts of wind and heavy rain made it too dangerous to summon a throng they initially expected to number up to 250,000 strong.
Story: Are you in Irene's path? Share photos, if it's safe to do so New JerseyTransit trains will stop running at noon Saturday, Gov. Chris Christie said Friday.
Aiming to speed up evacuations, Christie also suspended tolls on all parts of the Garden State Parkway south of the Raritan River and the Atlantic City Expressway.
Summer resort towns were emptying as officials ordered mandatory evacuation of the popular tourist areas along the state's coastal barrier islands.
Story: Irene to bring outages, scattered shortages of gas
Hundreds of thousands of people were likely to be affected by the orders, which included evacuation of such heavily visited towns as Wildwood, Ocean City and Avalon, all in Cape May County where the summer tourist population is typically 750,000 people.
Traffic was jammed for some 20 miles on the Garden State Parkway, said Mike Durkin, who drove home to Jenkintown, Pa., from the Jersey shore.
"I think there is a lot of nervous energy," he said. "There are people who have been there for 30 years who always rode out the storms before. A neighbor told me he just wasn't going to take a chance on this one though," he added.
Video: Christie issues stern warning of Irene to N.J. residents All 11 of Atlantic City's casinos were ordered to close by noon Saturday, he added. The city's casinos have shut down only twice before, in 1985 for Hurricane Gloria and in 2006 because of a state government shutdown.
PhiladelphiaMass transit in the city and suburbs will be shut down early Sunday morning, officials said Friday.
Interactive: Hurricane facts, figures & preparation (on this page)ConnecticutGov. Daniel Malloy declared a state of emergency and warned there could be prolonged power outages if Irene dumps up to a foot of rain on already saturated ground.
He said emergency responders must be ready in event of any evacuations from heavily developed urban areas. "We are a much more urban state than we were in 1938," he said, referring to the year that the so-called "Long Island Express" hurricane killed 600 people and caused major damage with 17-foot storm surges and high winds.
At Mystic Seaport, a popular "living history" museum that depicts 19th century New England seacoast life, staff members were hauling parts of the collections to higher ground. The museum will be closed on Saturday and Sunday as staffers load up sandbags.
Story: Airlines begin canceling flights as Irene nears
BostonWhile some residents flocked to the supermarket for bottled water and nonperishable food, others rushed to the local hardware store.
"Our number of customers has tripled in the last day or two as people actually said 'wow, this thing is going to happen,'" said Jack Gurnon, owner of Charles Street Supply, a hardware store in Boston's wealthy Beacon Hill neighborhood.
Tape for windows, flashlights and batteries were flying off shelves, but Gurnon said people were worried about flooding and have been scooping up sump pumps, too.
Rhode IslandThe towns of Narragansett and South Kingstown on Friday announced mandatory evacuations for residents in flood-prone areas for no later than 10 a.m. Sunday.
FloridaWhile avoiding a direct hit, the state did see the first U.S. injuries from Irene when eight people were washed off a jetty in West Palm Beach on Thursday by a large wave churned up by the storm. All survived.
BahamasIrene exited the northernmost part of the archipelago by midday Friday.
The government said the storm knocked out communications to islands such as Eleuthera and Abaco and that only partial reports of damage were available.
No reports of deaths or injuries were received, but 70 homes on the southern island of Acklins were destroyed, 29 sustained major damage and 84 received minor damage.
The capital sustained relatively minor flooding and damage.
Insured losses in the Caribbean from Hurricane Irene will be between $500 million and $1.1 billion, risk assessor firm Air Worldwide said on Friday, adding that the Bahamas will account for more than 60 percent of the loss.
The Associated Press and Reuters contributed to this report