By Ann Thelen
Nearly six months after Iowa’s historic derecho, the weather phenomenon that wreaked havoc on parts of the state continues to make headlines. Recalling the power outages and massive destruction from trees and winds, statewide leaders ushered in the new year by remarking on the storm.
“Iowans are well-accustomed to the extremes of Mother Nature’s temper, but the derecho in August was unlike anything we’ve seen. Hurricane-force winds recorded as high as 140 miles an hour raged across our state,” said Gov. Kim Reynolds in her 2021 Condition of the State Address in January. “Over one-third of our counties impacted; 584,000 households left without power; thousands of homes damaged. It was a disaster of unprecedented scope.”
Maj. Gen. Ben Corell delivered his condition of the Iowa National Guard address to the Iowa Legislature and detailed how the Guard provided more than 200 soldiers and airmen to communities hit by the hurricane-force derecho. Their focus was on supporting power restoration in Linn County, and Guard members removed over 1,400 loads of debris totaling more than 15,000 tons from 593 city blocks.
A top cause of outages
While the storm caused unprecedented damage, it also reinforced the role trees and other vegetation can play in disrupting safe and reliable electric service in all types of weather. It’s why Iowa’s electric cooperatives rigorously implement strong vegetation management programs.
“Trees are one of the top two causes of outages. In the past two years, they have been the No. 1 cause of outages,” says Jeremy Richert, CEO and executive vice president, Maquoketa Valley Electric Cooperative. “On average, it also takes nearly twice as long to restore power to member-consumers from tree-related outages.”
Richert cites data gathered from analyzing every outage at the co-op, which serves 14,000 members in nine east-central Iowa counties.
“The average time to restore power to member-consumers from an outage that is not tree-related is 1 hour, 12 minutes,” he explains. “That’s compared to an average of 2 hours and 20 minutes for every outage caused by trees.”
Maquoketa Valley Electric Cooperative’s vegetation management program includes a systematic, planned program where every area within its service territory is examined annually as part of the co-op’s drive-by inspection program. This program identifies where trees and other vegetation are growing too close to power lines and equipment, and those trouble spots are trimmed or sprayed by the co-op’s maintenance crews.
In addition, the co-op uses technology to identify system faults that cause blinks but not necessarily outages, such as branches rubbing against power lines. By continually tracking those things in real-time, crews can take care of issues before they become bigger problems.
Beyond what’s just below power lines
“Whether it’s a derecho, thunderstorm, ice storm or wind, it’s often the trees that are larger and a bit farther out, which cause more problems than the vegetation right below the lines,” Richert explains. “They might not look that close, but when they go down in a weather event, they fall onto the line, breaking poles and pulling the lines down.”
He adds, “This is why it’s so important for us to maximize and clear out the right-of-way as much as the property easement allows so that we can stop trees from falling onto power lines and equipment.”
During the derecho, 51% of Maquoketa Valley Electric Cooperative’s outages involved trees and accounted for 73% of the total time member-consumers were without power. Richert says the trees would have eventually been a problem with or without a derecho.
Managing trees in every season
T.I.P. Rural Electric Cooperative, which serves more than 6,300 member-consumers in east-central Iowa, also felt the impact of the derecho. Like electric co-ops across the state, maintaining a strong vegetation management is a necessity in every season.
“Our vegetation management program to inspect our entire system on annual cycles – cutting and spraying where necessary – has improved the number of outages and the duration of outages,” explains, Dean Huls, general manager, T.I.P. REC. “For safety and reliability of service, it’s imperative we have a strong program.”
Although trees are an everyday problem for power lines and equipment, storms draw attention to the problem.
“With the derecho, over 80% of our outages and infrastructure damage were from trees,” Huls says. “When looking at our system map from the derecho, it’s easy to see where the damage was from straight-line winds, and the rest of the damage was from trees. The trees caused most of our outages. Crews spent all day – day-after-day – clearing trees before power could be restored. Many out-of-state lineworkers who were helping with restoration efforts said they have never before in their career spent so much time clearing trees.”
Trees and shrubbery have an important place in our communities. Your local cooperative works hard to make sure trees also have a positive role in the overall safety and reliability of electric systems. Contact your electric cooperative if you have questions about its vegetation management plan.
Ann Thelen is the editor of Living with Energy in Iowa.
Downed power lines and equipment can still be energized, and if contact is made, it can result in serious injury or death. In the event of outages with damage, always check with your local electric cooperative before cleanup begins. Tree limbs that grow near power lines can be unsafe. Never trim trees near power lines; if you see a tree growing too close to power lines, contact your electric co-op to report it so trained staff can prune for you.
Before deciding to plant a tree, contact your local electric cooperative. The staff can advise proper placement to ensure the tree will not become a future hazard to electric equipment.
Some electric equipment is visible overhead, but some utility services also may be buried in the ground on your property. Iowa law requires that you always call 811 a minimum of two days (excluding Saturday, Sunday and legal holidays) in advance to schedule underground utility lines to be located and marked before initiating any digging or excavating project. If an underground utility line is hit while digging, it can cause serious injuries, disrupt service to entire areas, and potentially result in fines and repair costs.