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Municipalities are advised to be mindful of building, drainage and outdoor safety considerations in the coming months, amid forecasts of a stronger El Niño this fall and winter.
With a strong El Niño expected to influence weather patterns this fall and winter, municipalities have good reason to watch the forecast and review seasonal preparedness plans.
El Niño, the warm phase of a naturally occurring climate pattern in the Pacific Ocean, can alter the jet stream and influence temperatures, precipitation, and storm tracks thousands of miles away. The current event is gaining strength quickly and is expected to intensify through the fall, likely peaking sometime between October and January.
In its Aug. 13 update, the National Oceanic and Atmospheric Administration reported a greater than 90% chance of a very strong El Niño during the fall and winter of 2026-2027, and a 69% chance it could exceed the strength of any El Niño on record since 1950.
A stronger El Niño can make certain weather patterns more likely, but does not guarantee them. That uncertainty matters especially in New England, where conditions can vary considerably from one El Niño event to another.
Past strong El Niño events in the region have generally brought warmer-than-average temperatures, although no two seasons are alike. At the same time, El Niño tends to suppress Atlantic hurricane development, and forecasters have lowered expectations for hurricane activity this season.
Still, the more likely scenarios are worth considering when planning for fall and winter.
Rain and temperature swings
Historically, strong El Niño events tend to favor warmer winter temperatures in the Northeast. Local forecasts point to above-normal temperatures, more precipitation, and the possibility that some storms produce rain or mixed precipitation rather than snow.
A recent Boston Globe analysis adds that strong El Niño winters can bring more thaws, fewer sustained stretches of deep cold, and an uptick in coastal storms such as nor’easters.
For municipal buildings, a milder winter does not necessarily mean fewer weather-related concerns. More frequent transitions between rain, snow, ice, and thawing conditions can contribute to freeze-thaw cycles, ice dams, damaged flashing and roof membranes, blocked drainage, and water intrusion.
MIIA advises communities to maintain proper insulation, ventilation, and roof drainage to help reduce freeze-thaw damage. If snow is already present, rain can also add significant weight to accumulated snow and ice, increasing stress on roofs. Monitoring roof conditions, keeping drains functional, and addressing uneven snow and ice accumulation remain important even during a warmer winter.
A test for drainage
Heavy rain can quickly expose existing building vulnerabilities. MIIA recommends keeping roof drains, gutters, and stormwater drains clear, checking sump pumps and known water-entry points, and confirming that water sensors and alert contacts are operational. Buildings with basements or a history of water intrusion may warrant closer attention.
MIIA’s water-loss prevention guidance also recommends knowing the locations of water and utility shutoffs and maintaining building schematics, so staff can act quickly when a leak or water loss occurs.
Coastal communities have an added concern: NOAA has warned that El Niño can contribute to more frequent high-tide flooding along parts of the East Coast by influencing storm tracks and storm surge. NOAA provides water-level forecasts to help track changing coastal conditions.
Different vulnerabilities
Even with Atlantic hurricane activity expected to be lower overall, damaging storms remain possible. Coastal storms, nor’easters, and severe thunderstorms can still bring strong winds, power outages, and property damage.
Ahead of significant storms, MIIA advises inspecting rooftop equipment, trimming dead and damaged tree limbs, securing outdoor equipment and other objects that could become airborne, and testing emergency generators.
Preparedness extends beyond the physical building. Communities should review emergency response roles, backup communications, and procedures for maintaining essential operations during outages. Staff should know which contractors and vendors to contact during an emergency, and who has authority to make time-sensitive response decisions.
Agility Recovery, a MIIA partner, also recommends establishing emergency communications before a storm and taking steps to protect critical equipment and records from potential flood exposure.
Seasonal outlooks can’t tell us exactly when a storm will hit or whether winter will be snowy, icy, or rainy, but they can indicate which conditions are more likely. With El Niño expected to strengthen into fall and winter, the outlook can serve as a useful planning tool. It’s a good time to review known vulnerabilities, watch forecasts as they evolve, and make targeted preparations now to protect municipal buildings, employees and operations.
MIIA members can access a range of preparedness and risk mitigation resources, including seasonal preparedness checklists, at emiia.org/risk-management-resources.
Written by Jennifer Ranz