CHICAGO — The summer derecho that rattled windows and ripped down trees across the Midwest caused an estimated $11 billion in damage, becoming the costliest storm event to occur in less than 24 hours in at least four decades.
That’s according to the National Oceanic and Atmospheric Administration, which this month released its annual report detailing the billion-dollar-plus weather and climate disasters to strike the United States. A record-breaking 22 disasters caused $95 billion in damage in 2020.
Last year was the sixth in a row to have 10 or more separate billion-dollar disaster events, said Adam Smith, a NOAA climatologist.
“For 2020 to have more than doubled that standard, at 22 separate billion-dollar disaster events, shattering the record of 16 events that happened in 2011 and 2017, was really breathtaking,” Smith said. “It’s hard to believe. And hopefully we won’t have a year like 2020 for many years to come.”
Starting on Aug. 10, a speedy line of storms with remarkable endurance covered 770 miles in 14 hours. Beginning in southern South Dakota and hitting gusts higher than 90 mph, the derecho flattened millions of acres of crops, tipped over semitrucks and snapped trees apart on its path toward Ohio.
Its $11 billion in damage made the derecho the second-costliest severe storm event out of 128 that met the billion-dollar mark since 1980. The only severe storm that eclipsed the derecho in cost was the southeastern tornado Super Outbreak in 2011 that lasted for four days.
But, Smith said, “What makes the derecho interesting is that historically it produced the most damage in the least amount of time.”
The storm hit everything: homes, businesses, vehicles, the agricultural economy.
Justin Glisan, Iowa’s state climatologist, was at his Des Moines home when the storm arrived. His wife and dog headed to the basement. Before joining them, he looked out the back window.
“It was just a wall of dark,” Glisan said.
Glisan said his predecessor coined the term “derecho” at the University of Iowa, drawing from the Spanish word that can mean “straight on.”
“We can think of them as a line of self-perpetuating thunderstorms,” Glisan said.
A neighbor’s downed maple tree struck the gas main outside of the house, causing a gas leak. A fight or flight response kicked in, Glisan said, and the family ended up in a large parking lot.
“Given that we were surrounded by all these old-growth trees, I’m like, where can we go?” Glisan said.
They didn’t have gas or electricity for five days. Damage to the home ended up in the tens of thousands of dollars.
One of the hardest-hit areas was Cedar Rapids, Iowa, where 90% of structures were estimated to have been damaged and more than 1,000 homes destroyed, according to a NOAA report. More than 100,000 people were without power for days.
In Chicago, the derecho downed more than 550 trees in city parks alone. More than 800,000 people lost power in the Chicago area. At least 15 tornadoes were confirmed in northern Illinois and northwest Indiana.
The storm’s winds subsided as it moved east, but damage continued as far as Ohio. In a mobile home in Indiana, a woman and child were trapped during the storm, leading to the woman’s death.
The effects of climate change appear in the increasing weather extremes that might fuel a billion-dollar disaster.
“I think of the atmosphere as a pendulum,” Glisan said. “We’re seeing that pendulum start to swing farther up and down, from side to side, the wets getting wetter and the drys getting drier is very concerning.”
Severe storms can be connected to climate change, said Trent Ford, the Illinois state climatologist. But variability and specific conditions needed to fuel the storms make that connection more complex.
But climate change can compound threats.
“We have background weather variability like a derecho,” Ford said. “But because of other impacts of climate change, it makes our entire system more vulnerable to that derecho.”
In Iowa, Glisan started calling it the “drought-cho.”
Parts of west-central Iowa were already experiencing severe drought, with precipitation deficits going back a year, Glisan said.
“We had already had drought-stressed, moisture-stressed corn and beans in that part of the state,” Glisan said. “So you put the derecho on top of it and you get massive agricultural losses.”
In areas where drought hadn’t yet taken over, “the derecho took over for it,” Glisan said.
Initial estimates showed 3.5 million acres of corn and 2.5 million acres of soybeans damaged or destroyed, Glisan said.
“I talk with and I think of farmers often because they have enough on their plate to begin with. And then you put a drought and a derecho in the same year, on top of a global pandemic,” Glisan said. “It’s a lot.”
In 2019, the second-wettest year on record, flooding afflicted large swaths of Illinois. The Mississippi River and its tributaries caused an estimated $6.2 billion in damage and contributed to the deaths of four people across 13 states, according to NOAA.
Flooding wasn’t as prevalent last year, in part because there was less precipitation and it was less frequent, Ford said. The year was still wetter than average, but it couldn’t compete with 2019, and there was on average more time between rainfall events.
“It gave us the opportunity to have these dry periods of time, even just a few days extra where the soil could dry out, the small tributaries and creeks could flush out into the larger rivers and prepare for the next precipitation event,” Ford said. “And so we didn’t have nearly as much runoff. We didn’t have nearly as much backing up of those larger rivers and streams.”
Many of these high-cost disasters are inherently unpredictable, Ford said. But the outlook for the Western United States is leaning dry.
“The concern for drought and drought-related impacts is there again, really from the Great Plains westward,” Ford said.
Since NOAA tracking began in 1980, 285 disasters have met or topped costs of $1 billion, for a total nearing $1.9 trillion. The majority are severe storm events; some of the costliest and deadliest are hurricanes.
The overall annual cost average is about $46 billion. Last year’s $95 billion cost, the fourth-highest adjusted for inflation since 1980, is more than double average.
The highest-priced disasters last year ranged from the $19 billion in devastation wrought by Hurricane Laura to the $16.5 billion Western wildfires to the derecho — which contributed to four deaths and was the year’s third-costliest disaster. Hail storms in April that affected Illinois also made the list, as well as a few other severe storms throughout the year, including a January storm that tore into the Lake Michigan shoreline.
The swelling number and cost of disasters comes as global temperatures also topple records. Earth’s global average surface temperature in 2020 tied for the hottest year on record, according to a NASA analysis. NOAA placed 2020 in second place, just behind 2016. It was the fifth-warmest year on record for the United States.
The climbing number and costs of the disasters are connected to more people and assets exposed to risk, especially when compounded with already vulnerable coastal locations or river flood plains.
“And then lastly, climate change,” said Smith, the NOAA climatologist. “Which is clearly playing an increasing role in the increasing frequency of some types of these extremes that lead to billion-dollar disasters.”
