Overview In its October 2020 review,
NOAA updated its database of billion-dollar disasters to include this event (along with other disasters from the summer season) with preliminary estimated damages averaging 7.5 billion dollars, before upgrading the estimate to $11 billion. it is the most costly thunderstorm in US history.
Utilities and telecommunications disruption instrument on NASA's
Suomi NPP satellite animated before and the days after the derecho showing widespread power outages.|left Utility disruption and infrastructure damage occurred in much of the storm's path. Early estimates showed more than a million customers without power. Between August 10 and 13, 1.9 million customers were affected by 1.4 million maximum simultaneous outages—759,000 in Illinois, 585,000 in Iowa, 283,000 in Indiana, and 345,000 in other states, including Missouri, Wisconsin, and Michigan. Three days after the derecho, over 100,000 customers in Illinois, and 200,000 in Iowa, remained without power. The
Duane Arnold Energy Center cooling towers were damaged and the nuclear reactor was shut down permanently. By August 23, Alliant announced that power had been restored to 99 percent of their affected customers.
Mediacom, a telecommunications company, reported 340,000 customers
lost Internet access in the affected states.
Property damage The storm's winds caused wide-scale damage to plants, particularly trees, snapping large limbs, ripping off branches, and even felling or uprooting whole trees, often damaging houses and vehicles, as well as electrical and telecommunications infrastructure. Houses sustained significant damage to roofs, windows, and siding. Commercial and industrial property also sustained major structural damage from the storm. Large vehicles (such as
semi-trailer trucks and
recreational vehicles) as well as
mobile homes were blown over, sent flying, or destroyed.
Agricultural damage Farmers in Iowa, a major agricultural state and top
corn producer in the US, found their crops had been flattened and agricultural infrastructure such as silos, grain bins and grain elevators imploded by the storm. The crop damage was visible in satellite imagery, which the
USDA called impressive. NASA researchers assisted in satellite image analysis of derecho crop damage. The USDA's
Risk Management Agency reported that 57 of Iowa's 99 counties, with of crops, had been in the derecho's path. This is almost 66 percent of the of corn and
soybeans planted in 2020, or 45 percent of the state's total of
arable land. The average projected yield for the state was nearly halved, from to . Prescient Weather CEO Jan Dutton estimated that had been destroyed or degraded, a small portion of the tens of billions of bushels the US produces annually. The agricultural damage of the derecho was compounded by a concurrent
drought affecting 31 counties. Farmers preferred drought to wet conditions in the wake of the derecho damage, as wet conditions would induce rot and make it harder to harvest the flattened crops.
Nebraska In eastern Nebraska near
Tekamah and
Fremont, some of earliest storm damage occurred. The National Weather Service issued a warning at 8:45 a.m., with
Omaha reporting its first damage just eight minutes later. Winds reached , tree damage was significant, downed limbs blocked some roads. At least one person was injured. In
Omaha, the state's largest city, over 50,000 were left without power, a couple thousand remained so for two or three days.
Iowa taken from the
MODIS aboard NASA's
Terra satellite showing widespread agricultural and foliage damage resulting from the derecho.|left Affected towns and cities advised residents not to travel due to damage. City-wide and county-wide
states of emergency were declared. On August 13, Iowa Governor
Kim Reynolds issued a state-level disaster proclamation for 23 of
Iowa's counties, Several major roads in Iowa City were closed due to storm debris, including
Interstate 380 between Iowa City and Cedar Rapids. By August 16, the Iowa Governor's office estimated that the storm severely damaged or destroyed over 8,000 homes and caused $23.6 million in damage to public infrastructure. The cost of cleaning up debris from the storm was estimated at $21.6 million. Lake Macbride State Park, Palisades-Kepler State Park, Pleasant Creek State Recreation Area, and Wapsipinicon State Park were closed through the end of August for cleanup and repair. On August 17, President Trump partially approved Gov. Reynolds' request for a federal disaster declaration. On September 11, it was announced FEMA added seven additional Iowa counties (for a total of 23) to the August 17 federal disaster declaration, as well as the
Sac and Fox Tribe of the Mississippi in Iowa. In an October 2020 article, Emma Hanigan, an
urban forester for the
Iowa Department of Natural Resources, said that the impact on the state's trees will be felt for decades. In 2025, it was estimated a total of 7.07 million trees combined between forests and urban trees were damaged across Iowa by the derecho.
Cedar Rapids area . Approximately 65% of the tree canopy was destroyed city wide.
Utility damage and outages After the storm, Linn County peaked at over 95 percent power loss to residents due to
infrastructure damage, with Cedar Rapids experiencing a maximum 98 percent power loss. Thousands of electrical poles and miles of wire were downed; many residential
gas connections were also broken. On August 14, a hundred engineering and support personnel of the
Iowa National Guard were activated to assist the region. A week after the storm, 75,000 Iowans, most of them in Linn County, still lacked electricity. There were 40,000 Iowans in Cedar Rapids left without power up to at least August 17. On August 19, the Linn County
Rural Electric Cooperative announced 99 percent power restoration to its customers. By September 22, hundreds of Mediacom and ImOn customers still remained without internet service.
Property damage on August 19.|left|alt= Almost every structure within the Cedar Rapids city limits, including residences, 20 schools, and businesses, was damaged in some way, much of it severe, some of it catastrophic. Hundreds of thousands of trees, for which Cedar Rapids was known, were severely damaged or felled by the storm with both Cedar Rapids and nearby
Marion estimated to have lost half or more of their tree canopy from the storm; professional
arborists and state
foresters urged residents to seek professional help for their tree damage, saying it could take months to clean up. Many local businesses were forced to close, some indefinitely due to damage. By September 4, 2020, utility workers had installed over 3,400 new poles along with of wiring in the Cedar Rapids area after repairing most of the main electrical infrastructure in the city. On November 9, 2020, Dr. Melanie Giesler, a local physician, said increased allergies in the area were likely due to the derecho damage, spurred on by dust, debris, and mold growing on dead plant matter. In July 2022,
The Gazette reported that nearly two years after the derecho, owners of homes with
historic preservation concerns were still repairing antique windows damaged by the storm. Local groups and trusts were reported to have organized workshops for affected homeowners about how to properly restore this type of construction.
Debris collection and tree removals On August 21,
Marion city officials announced 98 percent of its streets were cleared and over 7,000 truckloads of debris had been removed. A month after the storm, Cedar Rapids had completed the first pass of storm debris collection on only 37.5 percent of its streets. By September 28, the city had removed 53,598 truckloads of debris for an approximate total of . As of November 24, 2020, cleanup was ongoing with the city currently working on the final public collection of non-organic debris. Collection of organic/tree debris is continuing indefinitely with the city having removed of organic debris to date; the trimming of damaged tree limbs in the public
right of way is 73 percent complete.
Des Moines metropolitan area In the
Des Moines metropolitan area, over 132,000 customer experienced outages, according to MidAmerican. The city said on August 21 that cleanup was slower than desired, estimating that damage cleanup could take up to six weeks. It planned to lease equipment from contractors to accelerate cleanup. A
Hy-Vee grocery store there was found by the
Iowa Department of Natural Resources to have
illegally dumped of spoiled milk into
storm sewers, contaminating a local waterway. The company assisted the state in cleanup efforts, blaming misinformed employees.
Buccaneer Arena, home ice of the
Des Moines Buccaneers minor-league hockey team, sustained significant roof damage. One week after the storm, nearly 7,000 residents of the city were still waiting for power restoration; 99 percent restoration was achieved on Aug 23. The damage to public parks in the city and surrounding
Marshall County was "extensive", particularly to trees. Damage metrics released on September 1 showed nearly 2,800 buildings were damaged or destroyed in the storm, more than the
2018 EF3 tornado which hit the city. City cleanup for the derecho is estimated around $4 million, of which
FEMA and the Iowa Homeland Security and Emergency Management will assist for reimbursement. By August 20, the city had hauled away of debris, almost triple the amount of the 2018 tornado. By late October, Justin Nickel, the city's public works director, said debris collection and cleanup were nearly complete for the city. Riverside Cemetery, a century-old burial site located in the city, remains littered with debris as the city struggles to raise money for its care.
Illinois |300x300px|left Across the state of Illinois, high winds and fifteen weak tornadoes, the majority of the derecho's tornadoes , caused variable damage to buildings, trees, and vehicles. Over 800,000 Com Ed customers lost power.
Confirmed fatalities In
Fort Wayne, Indiana, a woman was killed when high winds tipped over her mobile home. In
Poweshiek County, Iowa, Emergency Management confirmed the deaths of two: a
Malcom woman in her 40s killed when a tree fell on her porch and a
Brooklyn man in his 40s, a city employee and
electrician, killed by electrocution from a downed power line he was attempting to repair. == Responses and criticism ==