Regional Super El Niño Impacts: Northeast U.S.

There are differences among seasonal forecast models, and in areas where those differences are larger, confidence in the forecast is lower. We don’t yet know which model will be the most accurate. Overall, the six seasonal forecast models used as part of the North American Multi-Model Ensemble suggest higher confidence of a wet winter across the Northeast region. This is consistent with the broader shift in odds during El Niño events.    

These seasonal forecast models also suggest increased confidence that winter temperature, on average, will be warmer than average. The agreement among models does not mean there will definitely be reduced snow or ice, but only that the winter temperature overall is more likely to be a few degrees warmer. 

Natural resource managers can start planning for how they might manage for wetter conditions, including very wet conditions that might cause ponding or flooding. While very wet conditions are not guaranteed this winter, the odds are shifted toward this outcome. In addition, coastal land managers may want to consider the potential ways to adapt to more coastal storms and nor’easters that could produce inundation and overwash events. Big snowfall events are also more likely (but not guaranteed), and some management might warrant consideration of impacts from repeated large snowfall events.  

• More frequent coastal storms and nor'easters increase beach and dune erosion, tidal and salinity shifts, and saltwater intrusion into freshwater habitats.
• Increased storm frequency and heavy rainfall can increase the risk of inland flooding and runoff-driven water quality degradation, damage nesting sites for turtles, coastal birds, and damage stream habitat through sedimentation and scouring. 
• Warmer winters can worsen or expand the range of invasive species, pathogens, and fungal diseases. Warmer winters can reduce cold-water refugia important for some species. 
• Big snowfall events can lead to increased winter recreation (snowmobiles, skiing), which can degrade soil structure and vegetation. 
• Fluctuating snowfall can lead to a loss of stable snow cover and damage the subnivean zone that protects plants, microbes, and small mammals from lethal freeze-thaw conditions. 
   

• Where wetter conditions or repeated storms could cause significant impacts, managers can take low-regret preparedness actions now, such as checking drainage and water-control structures, identifying vulnerable infrastructure or habitats, and preparing for temporary closures or other operational responses. 
• Managers can identify key conditions to monitor, such as water levels, soil saturation, salinity, or erosion, and use those observations to guide management decisions as the winter unfolds. 
• Repeated flooding, erosion, or saltwater intrusion may create cumulative impacts that are harder to reverse over time. Managers may want to watch for locations where these impacts are becoming more persistent and consider whether different management approaches may eventually be needed.