The Effects of Hurricane Irene in New York were the worst from a hurricane since Hurricane Agnes in 1972. Hurricane Irene formed from a tropical wave on August 21, 2011 in the tropical Atlantic Ocean. It moved west-northwestward, and within an environment of light wind shear and warm waters. Shortly before becoming a hurricane, Irene struck Puerto Rico as a tropical storm. Thereafter, it steadily strengthened to reach peak winds of on August 24. Irene then gradually weakened and made landfall on the Outer Banks of North Carolina with winds of on August 27. It slowly weakened over land and re-emerged into the Atlantic on the following day. Later on August 28, Irene was downgraded to a tropical storm and made two additional landfalls, one in New Jersey and another in New York. The storm quickly began to lose tropical characteristics and became extratropical in Vermont.
Preparations Governor of New York Andrew Cuomo declared a state of emergency on August 25, urging the Office of Emergency Management to prepare for a possible landfall or direct hit from Irene. Cuomo ordered the deployment of 2,000 National Guard troops and oversaw their departure from the 69th Regiment Armory in New York City, and stated that the Guard would assist police, the Metropolitan Transportation Authority (MTA) and the Port Authority in New York and Long Island.James Barron, "New York City Shuts Down Amid Flooding Fears" (August 27, 2011), The New York Times. A mandatory evacuation order for low-lying areas of New York City was issued at 2:00 p.m. on August 26. A day prior, New York City Mayor Michael Bloomberg had announced that the city would prepare to create "an enormous shelter system" for residents without access to higher ground. President Barack Obama issued a state of emergency declaration for the New York metropolitan area, freeing federal disaster funds, and tasking the Federal Emergency Management Agency and the Department of Homeland Security to coordinate disaster relief efforts.
Beginning at 0900 UTC on August 26, a hurricane watch was issued from Sandy Hook in New Jersey to the mouth of the Merrimack River in Massachusetts; this encompassed Long Island and the southeastern coast of the state. Later that day at 2100 UTC, a previously issued hurricane warning was modified to include the coast from the Little River Inlet in South Carolina to Sagamore Beach in Massachusetts. Shortly after moving inland over New York, the hurricane warning was downgraded to a tropical storm warning at 1500 UTC on August 28. Early on the following day, all watches and warnings were discontinued.
The Staten Island University Hospital, Coney Island Hospital, New York University Hospitals Center, and the Veterans Administration Hospital began evacuating patients on August 26; sixteen nursing homes and adult care facilities were also evacuated. Possible rising seawater levels from storm surge and a predicted high tide led to a complete shutdown of the MTA, the nation's largest mass transit system. All subway, bus, and commuter rail service in New York City was halted at noon on August 27, with John F. Kennedy International Airport and LaGuardia Airport also closing.Hurricane Irene Wrecks Travel As NYC Area Airports Close, More Flights Cancelled, Gothamist, August 27, 2011 The New York International Fringe Festival cancelled all performances for August 27, and 28, as did all Broadway shows for those days. The United States Tennis Association cancelled special events planned for the 2011 US Open. Many New Yorkers likewise canceled their evening plans and spent the night at their own residences or with friends, having informal parties. Supermarkets did heavy business; there were jokes later about gaining "the Irene 15". Since they had to walk, drive or take taxicabs to go long distances due to the transit shutdown, city life took on a more relaxed character. "There was a community feeling", said one. "People were just stopping and talking on the sidewalk."
Impact
Flooding overwhelmed a number of local sewage treatment plants, since many of them collect and process storm runoff as well as wastewater. The state's Department of Environmental Conservation (DEC) reported on September 6 that at least 52 municipalities in the Hudson Valley had reported raw-sewage spills into local waters. "The collection plants were just overwhelmed" said one DEC engineer. However, the sheer volume of water from the storm mitigated the pollution by heavily diluting it. The approximate number of power outages were reported in the following counties: 36,000 in Albany County, 6,000 in Columbia County, 25,000 in Dutchess County, 7,000 in Fulton County, 18,000 in Greene County, 7,200 in Hamilton County, 2,500 in Herkimer County, 7,000 in Montgomery County, 24,000 in Saratoga County, 26,000 in Schenectady County, 9,000 in Schoharie County, 23,000 in Warren County, 4,500 in Washington County, and 60,000 in Ulster County. At times, the New York Thruway was closed from Westchester County to Albany.Sections of New York Thruway closed by flooding, Syracuse.com, August 29, 2011 Two weak EF0 tornadoes touched down in Queens and West Islip as well.
New York City
Upon making landfall on Coney Island, the storm produced a storm surge of and a storm tide of at Battery Park. Winds were lighter than the intensity of the storm in New York City. However, two locations in the city reported tropical storm force winds. A sustained wind speed of was reported at John F. Kennedy International Airport and LaGuardia Airport, respectively. On Manhattan, sustained winds were significantly less, reaching at Central Park. Rainfall in the area was moderate, with John F. Kennedy International Airport, LaGuardia Airport, and Central Park reporting , , and , respectively. Floods from Irene contributed to August 2011 being the wettest month ever in New York City.
In New York City, the Hudson River flooded, starting at approximately 8:50 a.m. on August 28, into Zone B as well as Zone A, mostly in the Meatpacking District along the Hudson River in Manhattan. At 9:15, the northern tube of the Holland Tunnel closed, but was soon re-opened. As of 9:20, the flooding was at about a foot deep. The water came within a foot of flooding the subway system and road tunnels. The police reported 30 arrests during the storm, some in domestic violence cases resulting from couples forced to remain inside. By 10:45, almost all of FDR Drive was closed.Due to flooding, the FDR Drive is fully closed, with the exception of E Houston St to E 34 St, MN. Consider alternate routes., NYCEM, Twitter, August 28, 2011
One man drowned at a marina in City Island in the Bronx, New York City while checking on his boat during the storm, while just north of New York City, one person was killed when an inflatable boat capsized on the Croton River. Two baseball games between the New York Mets and Atlanta Braves were postponed due to the effects of the storm.Mets postpone two games, ESPN, August 26, 2011
Long Island Extensive power outages occurred in both Nassau and Suffolk counties on Long Island. Almost 350,000 homes and businesses were without electricity, mainly due to heavy winds knocking down trees, which in turn knocked out many power lines.Jonathan Allen – "Long Island residents frustrated by power outages" – Reuters – August 29, 2011 – Retrieved 30 August 2011. Rising frustration among residents over the slow pace of power restoration led Cuomo to call on the Long Island Power Authority (LIPA) to replace system operator National Grid, whose contract is up for renewal. Orient Beach State Park was closed for 3 days due to storm damage.Orient Beach State Park Reopens, Patch.com, September 1, 2011
Another fatality occurred on the south shore of Long Island, when a windsurfer drowned in Bellport Bay.
Albany County In Albany County, numerous trees and power lines were reported down due to strong winds. This resulted in numerous power outages and road closures. There was also extensive flooding along the Normanskill Creek that resulted in significant property damage to homes located near the creek.
Orange County
The Ramapo's flooding was believed by residents of an area of Tuxedo east of the river which flooded severely to have been exacerbated by the failure of a dam at Arden. Rainfall there was recorded at , the most of any location in the county. Later investigation found that the earthen dam at Echo Lake, on a private preserve owned by descendants of rail magnate Edward Harriman, Arden's founder, had collapsed during the storm, sending an alleged 100 million gallons () into the river. Some residents reported an wall of water coming down the river; those with property along the river say it had never gotten that high in other storms. The dam had last been inspected in 1986 and found to be "low-hazard", meaning its failure would not severely impact any structures or roads in the area. Local officials were incredulous, noting the dam's proximity to the New York State Thruway, which had to be closed through there for two days as a result.
In Goshen, the Orange County seat, residents reported sewage backing up into their homes, and in some cases the streets. Vaccinations against tetanus and hepatitis were offered to rescuers before entering houses in some areas. District Attorney Frank Phillips reported that a flooded grand jury room at the Orange County Government Center, which was closed for the week after the storm, might have to be renovated due to mold growth. A day after it was reopened, rainfall from Tropical Storm Lee flooded it again, and it was closed indefinitely. County Executive Edward A. Diana pressed legislators to reach a decision soon on whether to repair the building or replace it, a topic long under consideration in county government. After years of contentious debate between preservationists and county officials, the building ultimately underwent a partial demolition and renovation, with roughly one-third of the complex demolished and replaced by a new addition while the remaining two original buildings were stripped and rebuilt. The renovated Government Center reopened in late 2017, following a $74 million restoration effort that had closed the complex since the hurricane damage of 2011. In the interim, the county's courts scrambled for space. The county's 170-year-old original courthouse, which had not been used for that purpose in 40 years, temporarily hosted civil cases.
Elsewhere in the county, parts the village of Washingtonville were under of water during the storm due to the flash flood of Moodna Creek. Some homes near the creek had to be condemned. Three weeks later, Moffat Library was closed down for repairs and cleaning from the of water in its basement. It would not reopen until late 2017.
In Harriman State Park, the beach at Lake Sebago was washed away completely and closed following the storm. The beach remained closed for more than a decade; in December 2025, Governor Kathy Hochul announced a $95.8 million reconstruction project for the site, with construction scheduled to begin in spring 2026 and completion targeted for summer 2027. Seven Lakes Drive was also closed through the park due to extensive storm damage.
Orange County's Cornell Cooperative Extension estimates that half of the county's of cultivated land was damaged, along with $1.5 million in farm infrastructure such as field roads washed away, soil covered in silt and land eroded.
Ulster County
In Ulster County, crop losses were estimated at $5 million. One farmer in Kerhonkson found his fields under of water from Rondout Creek, enough for him to use personal watercraft on the resulting lake well into September.