As winter weather moves into central North Carolina this weekend, utility crews are bracing for the possibility of multiday power outages — a familiar warning in a state that ranks among the hardest hit nationally by weather-related blackouts.
From ice storms to hurricanes, North Carolina has experienced more than 111 major weather-related power outages since 2000, according to U.S. Department of Energy data. That puts the state fourth in the nation, behind only Texas, Michigan and California.
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And the trend is moving in the wrong direction.
Nationwide, the U.S. has experienced about twice as many weather-related power outages in the last decade as in the early 2000s, according to a Climate Central analysis. Four out of five major outages reported between 2000 and 2023 were linked to weather — not equipment failures or cyberattacks.
Winter weather is a leading outage trigger
While hurricanes often cause the longest blackouts, winter storms are responsible for nearly a quarter of all weather-related outages nationwide. Ice, sleet and heavy snow add weight to power lines and trees, snapping equipment that was never designed to withstand prolonged freezing conditions — especially in the Southeast.
“A quarter inch of ice is typically when we start to see tree limbs coming down onto power lines,” Jeff Brooks, a spokesperson for Duke Energy, said. “Once you get to half an inch, the lines themselves can begin to sag and break.”
North Carolina sits in a vulnerable middle ground: cold enough to see ice storms, but without the cold-weather hardening common in northern states. When winter storms strike, outages can be widespread — and slow to fix.
Brooks said the length of outages often depends on both the scale and severity of the damage. When storms create thousands of separate outage locations, especially those involving broken poles or heavy tree damage, restoration can take longer as crews repair sites one at a time and prioritize larger service areas.
Why some outages last days, not hours
Downed lines are often visible and relatively quick to repair. Transformer failures are not.
Transformers, the equipment that steps electricity down from transmission lines and distributes it to homes, are among the most critical and time-consuming components to replace once they fail. When a transformer goes down during a major storm, restoration can take days, not hours.
Inside those transformers is oil that serves as both insulation and coolant. After outages, utilities often test oil samples to determine whether a transformer can be safely re-energized or whether internal damage has occurred.
“Most people don’t realize there’s liquid and solid insulation inside a transformer,” said Zach Holland, a chemist with Doble Engineering, an electrical diagnostics company that works with utilities nationwide. “Testing that oil is one of the fastest ways to tell whether the transformer is still healthy.”
If oil testing reveals electrical faults or internal damage, repairs can be extensive — and replacements may not be readily available during widespread storms.
Brooks said transformers play a critical role at multiple points along the grid — from substations that step down high-voltage transmission lines to the smaller transformers that serve individual neighborhoods.
If a large transformer is damaged, replacement can be complicated by supply constraints and manufacturing timelines, making prevention and early detection especially important.
If oil testing reveals electrical faults or internal damage, repairs can be extensive — and replacements may not be readily available during widespread storms.
Denis Lafrance, a senior director at Doble, said transformer-related outages are among the most difficult to resolve.
“The repair on any unplanned outage involving a power transformer can be difficult and time-consuming,” Lafrance said, noting that replacement lead times for large transformers can stretch up to five years.
Climate change is raising the stakes
Climate change is reshaping the weather patterns that most often knock out power — increasing the frequency, intensity and reach of storms that strain an aging electrical grid.
The nation’s electrical grid was largely built for the climate of the 20th century, not the extremes of the 21st. Above-ground power lines, transformers and substations are increasingly exposed to stronger storms, heavier rainfall, extreme heat and more volatile winter weather.
The Southeast — including North Carolina — has experienced more weather-related outages than any other U.S. climate region over the last two decades.
“We have seen, statistically, some increase in the frequency and severity of storms on our system in the last few years,” Brooks said.
At the same time, electricity demand is climbing, driven by population growth, electrification and energy-hungry data centers tied to artificial intelligence. That added strain increases wear on already aging infrastructure.
The human cost of losing power
Power outages are more than an inconvenience. Extended blackouts can cut off access to heating, refrigeration, clean water and medical equipment — risks that rise sharply during winter storms and heat waves.
Data shows that long-duration outages disproportionately affect medically vulnerable communities, particularly in the South and Appalachia. During prolonged blackouts, emergency rooms often see spikes in cold exposure, carbon monoxide poisoning from improper generator use, and complications for people dependent on electrically powered medical devices.
Preparing for a more outage-prone future
Utilities across North Carolina say they have invested heavily in grid improvements, including stronger poles, underground lines and “self-healing” technology that can automatically reroute power. But even with those upgrades, extended outages remain likely during severe weather.
Brooks said those technologies helped Duke Energy avoid millions of outage hours last year, but acknowledged that no system can fully eliminate storm-related outages.
“We can strengthen the grid, but severe weather will still cause disruptions,” he said. “That’s why we’re also focused on building a grid that can recover faster.”
Experts say reducing long outages will require both near-term adaptation — like grid hardening, better monitoring and faster testing — and long-term action to address climate change itself.
In its analysis, Climate Central said the most effective way to reduce long-term outage risk is to slow the pace of warming itself. Cutting greenhouse gas emissions, the group said, would ease growing stress on the power grid and give utilities more time to adapt.
For now, as winter weather approaches, utilities are urging customers to prepare emergency kits, charge devices and plan for the possibility that the lights may stay out longer than they once did.