Nor'easter-driven coastal flooding from New Jersey to New England
An unusually strong early-season nor’easter brought several days of coastal flooding, heavy rainfall, damaging winds and disruption to the northeastern United States in late September 2026. The slow-moving storm affected densely populated coastal communities from New Jersey to New England, with repeated high tides contributing to inundation of shorelines, bays and low-lying neighbourhoods (NOAA, 2026).
At least one fatality was reported; more than 100,000 customers lost power, voluntary evacuations were issued in vulnerable coastal communities and transport networks experienced widespread disruption (BBC News, 2026).
The event is notable because flooding was not driven by a single mechanism. Elevated coastal water levels, large waves and repeated high-tide cycles coincided with heavy rainfall, restricting drainage and increasing surface-water flooding in some locations (US News, 2026).
The nor’easter therefore provides an important example of compound flood risk in a highly developed coastal region, demonstrating why coastal and surface-water hazards need to be considered together when assessing exposure, potential losses and future resilience (Wahl et al., 2015).
Overview and timeline
During late September 2026, an unusually strong early-season nor’easter developed offshore of the US East Coast. Nor’easters are large storm systems that produce northeasterly winds along the Atlantic coast of North America. They develop along strong temperature contrasts between cold and warm air masses and can bring heavy rain, snow, strong winds, coastal flooding and beach erosion. Although they can occur at any time of year, they are generally more frequent and severe between September and April (AccuWeather, 2026a). Meteorologists warned that the coastal low could stall or loop near the coast between New Jersey and Long Island, prolonging strong winds, heavy rainfall and coastal flooding. The storm became a long-duration event, with persistent onshore winds, high surf, beach erosion and coastal inundation affecting the northeastern coastline across multiple tidal cycles (AccuWeather, 2026b).
A full moon occurred during the event, bringing high astronomical tide levels and increasing the risk of coastal flooding. The combination of elevated tides and prolonged onshore winds contributed to repeated flooding along shorelines, bays and tidal rivers. This event was primarily a coastal flooding event, although heavy rainfall also contributed to impacts in some areas. Rather than a single storm-surge peak, flooding persisted through multiple high-tide cycles as water levels repeatedly rose and fell with the tides over several days (The Weather Channel, 2026; NOAA, 2026).
Rainfall and coastal hazards
The September 2026 Nor’easter was characterised by a prolonged period of heavy rainfall, strong onshore winds and elevated coastal water levels affecting large areas of the northeastern United States. Rainfall totals were particularly high across southern New England, where several locations recorded more than 6 inches (152 mm) of rainfall during the event.
Parts of southeastern Massachusetts received between 6 and 8 inches (152-203 mm), while some communities had already exceeded 5 inches (127 mm) by 27 September (MassLive, 2026). Forecasts issued prior to the peak of the storm had warned that rainfall accumulations could reach 8 inches (203 mm) in the most heavily affected areas (The Guardian, 2026).
Further south, rainfall totals were generally lower but still significant. Forecasts indicated that eastern New Jersey would receive between 1 and 3 inches (25-76 mm) of rainfall, while parts of Long Island and southern New England were expected to receive between 3 and 5 inches (76-127 mm) (CBS News, 2026). In some areas of New Jersey, observed rainfall totals exceeded 4 inches (102 mm), compounding the effects of coastal flooding and restricting drainage during successive high-tide cycles (US News, 2026).
Coastal impacts were amplified by the storm's slow movement and prolonged onshore winds. Forecasts highlighted sustained coastal winds of 40-60 mph (64-97 km/h) from New Jersey to Maine, with gusts approaching 80 mph (129 km/h) around Montauk, New York (The Guardian, 2026). These conditions generated large waves, rough surf and elevated water levels along much of the Northeast coastline. Repeated high-tide cycles resulted in extensive coastal and back-bay flooding across parts of New Jersey, New York and southern New England, while prolonged wave action contributed to shoreline and dune erosion in vulnerable coastal areas (US News, 2026; 6abc, 2026).
Flood inundation and JBA flood maps
The event was notable for its compound flooding, with coastal flooding being a primary mechanism and an additional surface water component. JBA’s coastal and surface water flood maps are displayed below for some of the key locations impacted by the event, demonstrating the flood risk for these areas.
Impacts
As of 28 September 2026, at least one fatality had been confirmed in Brooklyn due to a falling tree, and states of emergency had been declared in New Jersey and New York (BBC News, 2026). Voluntary evacuations were issued in several low-lying coastal communities in New Jersey, including Manasquan and Sea Bright, and residents in flood-prone areas were advised to move to higher ground as roads became inundated by repeated tidal flooding. Authorities in New York City also urged residents of vulnerable basement apartments to relocate to safer locations ahead of peak flooding (Philadelphia Weekly, 2026). For public safety, many events were cancelled, including sporting and music events (BBC News, 2026).
The storm caused widespread disruption to infrastructure and transport networks. Fallen trees contributed to power outages affecting more than 100,000 customers across the Mid-Atlantic and New England states, disrupting homes and businesses. More than 500 flights were cancelled, and over 5,000 delays were reported across the United States, while numerous road closures and widespread travel disruption occurred due to floodwaters, fallen trees and other debris (The Guardian, 2026).
Flooding impacts were particularly severe in some coastal communities. In Manasquan, New Jersey, back-bay flooding exceeded 7 feet, leading to substantial inundation of low-lying areas and prompting evacuations and road closures (Fox Weather, 2026). Significant coastal erosion was also observed along parts of the New Jersey coastline. In response, the US Army Corps of Engineers began post-storm assessments of beaches from Long Beach Island to Cape May to evaluate the extent of coastal damage (6abc, 2026).
Notable historical events
The September 2026 Nor’easter flooding event occurred in a region that has experienced several major coastal and inland flood disasters over recent decades. The northeastern United States is particularly vulnerable to flooding due to its long, densely populated coastline, extensive urban development and exposure to both tropical and extratropical storm systems. Historic events have demonstrated how a combination of storm surge, high tides, intense rainfall and strong winds can produce widespread impacts across multiple states simultaneously.
The 1993 "Storm of the Century" was a powerful cyclonic storm that affected the eastern United States between 12 and 15 March 1993. The storm generated widespread coastal flooding, hurricane-force winds, heavy snowfall and tornadoes, resulting in more than 250 fatalities. Transportation networks were severely disrupted, with major highways and airports forced to close, whilst millions of homes and businesses lost power. The event remains one of the most significant multi-hazard weather disasters to affect the Atlantic coast of North America (Britannica, 2026a).
Hurricane Sandy (2012) caused destruction from the Caribbean to the US East Coast as it generated wind speeds of up to 100 mph and a significant storm surge that led to extensive coastal flooding. Large areas of Lower Manhattan were inundated, including critical transport infrastructure such as subway stations and road tunnels. The storm also caused widespread power outages and resulted in substantial damage to homes and businesses across New York and neighbouring New Jersey (Met Office, 2026).
More recently, Hurricane Ida made landfall in Louisiana in August 2021 before its remnants moved across the northeastern United States. In New York City, the Central Park gauge station recorded 7.13 inches of rainfall over 24 hours on 1 September 2021 (Weather.gov, 2021). This resulted in flooding at subway stations, parks, roads and properties throughout New York, as the city is only protected by coastal defences, which were unable to protect against intense rainfall (Technology Review, 2021).
These notable events, amongst others, are summarised in Table 2 and illustrate the wide range of flood mechanisms affecting the northeastern United States, including coastal storm surge, tidal flooding, river flooding and urban flash flooding.
Climate change
Although it is not possible to attribute an individual storm directly to climate change, there is evidence that climate change can increase the impacts associated with nor’easters. Rising sea levels along the US East Coast increase the baseline water level on which storm surge and high tides occur, contributing to greater coastal flood extents during storms (TIME, 2026). In addition, a warmer atmosphere can hold more moisture, increasing the potential for intense rainfall and enhancing the risk of compound flooding when heavy precipitation coincides with coastal inundation (TIME, 2026).
These factors are particularly relevant to the September 2026 Nor’easter, where flooding was driven by a combination of elevated coastal water levels, repeated tidal cycles and heavy rainfall affecting low-lying communities across the northeastern United States. Previous research has also shown that the interaction of storm surge and extreme rainfall can significantly increase flood risk in major US coastal cities, highlighting the importance of considering compound flood hazards when assessing future flood risk (Wahl et al., 2015).
Conclusion
The September 2026 Nor’easter demonstrated the vulnerability of the northeastern United States to compound flooding. Persistent onshore winds, elevated tides and heavy rainfall combined over several tidal cycles, producing coastal, back-bay and surface-water flooding across densely developed communities. The event highlights why coastal and rainfall-driven hazards should be assessed together rather than independently.
JBA’s high-resolution flood maps provide a consistent view of river, surface-water and coastal flood hazard, including detailed coverage for the United States.
JBA’s Global Climate Change Flood Maps extend this analysis into future climates, enabling users to explore how inland and coastal flood extents and depths may change under different warming and sea-level rise scenarios. Together with JBA’s climate change data and probabilistic models, these products help insurers, reinsurers, lenders and asset managers identify emerging risk hotspots, assess potential changes in financial loss and make more informed underwriting, investment and resilience decisions.
