Maine utilities brace for winter weather whiplash

Contributed by Bill Perry

In January, Maine’s second-largest utility, Versant Power, published a new version of its climate vulnerability study. The goal, according to a Versant Power spokesperson, is “to identify specific asset vulnerabilities and propose potential resilience measures to climate hazards including winter weather.” While hurricanes grab headlines, winter weather in North America has also become increasingly severe and unpredictable. Utilities in Maine have a front-row seat for that.  

“Over the last couple of years, the full force of winter in Maine has begun in December, instead of January, and lasts until spring,” says Joe Purington, president of Central Maine Power, the state’s largest electric utility. “These storms are also bringing precipitation at temperatures closer to 32 degrees, which can mean wet snow that’s heavy and causes damage.”  

Researchers have a name for what Maine’s utilities are facing: winter weather whiplash. By definition, winter whiplash includes shifts between extreme freezing and thawing as well as rain and snow. The effects are particularly acute for power lines. They are bearing increased ice loads that may exceed design limits.   

The whiplash effect may not be new, just more frequent. Mainers faced a devasting ice storm, quickly followed by snow, in 1998. The widespread ice storm struck utilities across southern Ontario, Upstate New York, New England, and eventually Maine. The ice snapped trees and toppled transmission towers. Because Maine was unaffected early on, power companies there had sent crews to help neighboring states. In turn, utility and tree crews came from as far away as North Carolina to help Maine. To support the effort, U.S. Secretary of Defense William Cohen, a Mainer, ordered the Military Airlift Command to fly lineworkers and their trucks to Maine.   

“Instead of these infrequent, historic ice storms, utilities are now seeing more frequent, historic differences in snow loading and icing patterns that affect forests,” says Dennis Fallon, executive director of the Utility Arborist Association. “Vegetation consistently lands in the top 5, if not higher, for outage codes. A well-funded vegetation program with experts who understand what’s happening on a local level and make local adjustments helps a utility improve reliability.”   

Fallon says a well-run utility vegetation management (UVM) program is 95 percent proactive and five percent reactive.  

Seeing the Forest for the Trees 

An arborist contracted by CMP surveys extensive storm damage in the Limerick, Maine area as part of CMP’s large-scale response to heavy, wet snow brought by a spring Nor’easter in April 2024. (Credit: Central Maine Power)

According to Versant Power, which has a service territory of more than 10,000 square miles stretching from Maine’s coast to the Canadian border, the changing winter weather patterns are affecting the landscape in new ways. Versant Power’s study, which the utility completed with the help of global consultancy ICF, notes that vegetation within and beyond rights-of-way faces a high degree of vulnerability. Ice and wetter, heavier snow now makes trees even more vulnerable to falling and breaking, leading to outages. 

The Versant Power report specifically states that “given the risk trees pose to utility infrastructure, maintaining the function of the vegetation management program in the context of a changing climate is crucial to maintaining safety and reliability across the Versant system.”  

Tina Morrill, a communications specialist for Versant Power, says, “With most of our outage threats coming from trees located outside of the normal clearance right-of-way, we implemented an enhanced risk tree program to remove whole trees located beyond the clearance zone.” 

Morrill added that the utility is also shortening pruning cycles, conducting LiDAR surveys of the transmission system, and, where possible, widening the rights-of-way on transmission and distribution lines.  

“If you think about our nor’easters, trees have grown in a way to withstand traditional northerly winds, but we’re now getting southerly winds, too,” adds Purington. “Trees from outside our legal right-of-way are also a leading causing outages.” 

With pine, spruce, and white birch, Maine is the most heavily forested state in the U.S. So, managing vegetation is top of mind for Purington’s CMP, which has an 11,000-square-mile service territory in central and southern Maine. For the last 30 years, research on multiple storms across the Northeastern U.S. has pointed to trees “as the leading cause of outages.” There is ample evidence that UVM programs improve reliability and cut the system average interruption frequency index, or SAIFI. For example, a University of Connecticut statewide study comparing 13 years of pruning using an enhanced tree pruning program versus nearby untreated rights-of-way found “ETT-treated conductors had storm outage rates that were 0.07 to 0.36 outages/km/year lower than untreated conductors or 35 to 180 percent lower than the service area’s average annual outage rate for untreated conductors.” 

Jon Breed, director of Corporate Communications for CMP, notes, “60 percent of our customers live within 20 miles of the coast, and that’s where you see the rain-snow line become an issue in warmer storms with different types of precipitation.”   

Despite the increased ice and snowfall in certain areas, Maine continues to go through drought cycles. In fact, nearly “85 percent of the state is in a moderate drought” reported the Piscataquis Observer in December 2024. This, say experts, means a percentage of the state’s trees have weakened. The dual threat from winter weather whiplash and changing winds spurred CMP to adapt its UVM practices to mitigate potential outages from broken limbs and fallen trees. For example, in the past, the utility’s vegetation crews would prune trees to a height of eight feet above the power line. Now, where allowed, pruning extends not only a distance of eight feet to each side of the line but from the line all the way skyward through the tree canopy in certain areas.   

“This sounds to me like CMP identified new risks and changed its UVM approach,” notes Fallon. “That’s the sign of a healthy vegetation program; one where you make adjustments based on data and other lagging and leading indicators that your tree experts collect.” 

Like Maine’s two largest electric utility companies, one of its smallest utilities Van Buren Light & Power–one of six consumer-owned utilities–makes vegetation management a priority. 

“With the increase in winter ice, we now prepare more for down lines and poles,” says Bill Schofield, manager of Van Buren Light and Power, which serves approximately 1,600 residential and commercial customers along the St. John River Valley bordering New Brunswick, Canada. “We have to focus on things that will make an impact because we only have two, two-man crews, two buckets, and a digger.” 

According to Schofield, winter ice storms have gotten to the point where “conductors stretch and touch other phases or trees fall under the weight and cut power.” 

Schofield’s approach is to prune along the utility’s lines every year, focusing most of the effort during two weeks in the fall. If a customer doesn’t want a tree and there is the potential that it could fall in the right-of-way and on a conductor, Schofield and his crews will prune it. Schofield will cut the tree to below the power and telephone lines and let the customer take it down from there.  

“Being vigilant about vegetation management saves us a lot of service calls, especially in the middle of the night,” adds Schofield. “Here, people understand power and why a tree needs to come down.” 

Connecting with the community 

A CMP lineworker repairs a distribution line after an impactful snowstorm in December 2023. (Credit: Central Maine Power)

Purington says relationships help CMP respond safely and expediently to the outages from winter weather.  

“Building and maintaining relationships with local communities helps in any storm,” says Purington. “Our team makes a point to know who we’re working with before storms ever happen; if there’s a change within an organization, we’re on top of that.” 

CMP stays constantly engaged with local governments, emergency management agencies, the media, and other utilities. This, says CMP’s Breed, speeds up problem-solving and communicating with stakeholders before, during, and after events. Last fall, Purington’s team invited many of Maine’s emergency management agencies and municipal contacts to learn about and provide perspective on CMP’s process for storm preparation, restoration, and reporting.  

CMP also carries out meetings like these with its contractors. During larger events, Purington says it is important to have a “natural web of communication” with contractors, from the initial point of forecasted storms through the entirety of the event. Communication helps ensure there is a mutual understanding with contractors about CMP priorities, and the type of winter conditions workers will face. 

Investing in utility-contractor relationships 

Central Maine Power (CMP) President and CEO, Joe Purington, speaks to representatives from the Maine Emergency Management Agency and other local emergency management agencies at CMP’s headquarters in Augusta, Maine as part of a coordination meeting held ahead of the 2024-2025 winter storm season. (Credit: Central Maine Power)

“Over the years, our relationship with contractors has become much closer,” says Purington. “There’s also been an evolution in technology, which CMP uses to communicate with contractor crews whether it is onboarding or relaying work assignments.” 

According to Mike Zappone, chief operating officer at Covington, La.-based Tempest Energy, a provider of storm restoration and utility consulting services, many utility contractors and their trade allies have evolved from “chasing storm work” to operating in a way that mirrors utilities. Zappone has seen both sides of the utility-contractor relationship having worked for Eversource before retiring and joining Tempest. 

“Contractors must work problems like the utilities that bring them on the property,” says Zappone. “If you’re going to work tens of thousands of hours and miles safely on a system, a contractor has to leverage technology.” 

According to Zappone, once a contractor knows a utility’s processes, they can reinforce that through online tools for health and safety briefings or mobile apps to reduce the time to confirm their availability for storm restoration. Making restoration happen safely and efficiently is about getting in lockstep with a utility, Zappone says, which can be especially challenging in winter weather. 

“If we invest in a relationship, we can help ensure long-term success,” says Purington. 

With the effects of winter weather whiplash events, experts say coordinating and equipping internal and external crews requires more planning. A plunge in temperatures will require the typical gear including tire chains, ice cleats, hand warmers, lock deicers, and cold-weather workwear. For transmission line work in remote areas, Versant will rely on winterized tracked ATVs and UTVs, pickup trucks, and occasionally helicopters.  

According to Versant Power’s Morrill, if there is significant damage to its system, Versant Power puts its line workers as well as external crews (supervised by qualified Versant personnel) in the field. 

If the weather whipsaws and rapidly warms, crews can face sleet, rain, and even flooding. In these situations, if it is safe to operate, Maine utilities will keep their crews on a job site to repair damage. As the conditions require different equipment for crews in remote areas, runners travel between the site and the service yards to keep lineworkers on the job. 

“More than in the past, we’ve had to brace ourselves for the effect of unusual winter weather patterns and pivot,” reflects Purington. “Planning and relationships are the keys to our continued success in the face of stronger, more frequent storms.” 


About the author

Bill Perry ([email protected]) is a New York-based freelance writer who has covered the utility, manufacturing and aerospace and defense industries for nearly 20 years.

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