(storm winds blowing) ♪♪ Justin Glisan: I had never seen clouds this dark and I had never seen it get so dark so rapidly.

♪♪ ♪♪ I've seen a lot of weariness.

This is just something that we didn't need on top of an already difficult situation.

The damage is widespread and the damage is real.

♪♪ (storms winds blowing) ♪♪ Justin Glisan: I've storm chased, I've been in severe weather events.

This was the first time that I had been very scared.

(storm winds blowing) Severe storms are a part of life in Iowa.

However, the number and intensity of these events has been on the rise.

Many of these catastrophic weather events have changed parts of Iowa forever.

As the level of devastation across the Hawkeye state increases, there are questions about what the future might hold with Iowa's Wild Weather.

♪♪ Funding for this program was provided by Friends, the Iowa PBS Foundation, as well as generations of families and friends who feel passionate about the programs they watch on Iowa PBS.

Funding for this program was provided by the Gilchrist Foundation, founded by Jocelyn Gilchrist, furthering the philanthropic interests of the Gilchrist family in wildlife and conservation, the arts and public broadcasting and disaster relief.

And by, the Claude P. Small, Kathryn Small Cousins and William Carl Cousins Fund at the Quad Cities Community Foundation to support nature programming on Iowa PBS.

♪♪ Support for this program has been provided by the Strickler family, in loving memory of Lois Strickler, to support programs that highlight the importance of Iowa's natural resources on Iowa PBS.

(storm winds blowing) In August of 2020, a collection of thunderstorms packing hurricane force winds, leveled large portions of landscape across eight Midwestern states.

The widespread event set a record for the nation's most expensive thunderstorm, causing more than $12 billion in damage.

Weather forecasters labeled the powerful storm a derecho.

The definition of derecho translates to straight or forward and describes particular wind patterns in supercell thunderstorms.

Before August 10, 2020, the weather term derecho was not a widely known term.

Mike Naig: No, I had never seen, frankly never heard of something like this happening.

And again, that's saying something because we're used to dealing with weather in agriculture, and even severe weather from time to time.

But this was something that was completely unheard of.

(crickets chirping) ♪♪ After that warm August day, many Midwesterners would make derecho a household word, now synonymous with a complex of severe thunderstorms responsible for carving a path of destruction 770 miles long across the Midwest.

Mike Naig: What is so distinct about that storm is frankly the length of time that it was on the ground.

I mean, you're talking from South Dakota to Ohio.

You're talking about a swath across the center part of Iowa, basically the center third of Iowa from river to river saw damage of some kind, not all of it severe, but some damage.

And then the intensity of the storm itself, the winds and then how long.

(storm winds blowing) Mike Naig: Those are things that make this really an unprecedented event.

♪♪ Described as a hurricane without an eye, the tempest did most of its damage in Iowa, wiping out millions of acres of row crops.

According to the Iowa Department of Agriculture, the derecho inflicted damage in more than 60 counties, with 36 experiencing massive levels of destruction.

In all, nearly one-quarter of the corn and soybean crops were damaged or destroyed.

Many farm families across Iowa faced gut-wrenching decisions after the storm.

Storage for harvested commodities on Iowa farms took a big hit as the rare weather event crushed grain bins like aluminum soda cans.

State of Iowa officials estimate 57 million bushels of stored grain at co-ops across Iowa had been compromised.

Millions of yet to be harvested bushels headed for on-farm storage were lying on the ground in need of a new home.

Mike Naig: The damage was so significant on some of these farms and you're looking at a crop that was damaged.

Where do you even start to start to clean up and rebuild?

And people just told me, well, we just got after it.

And people helped and neighbors came and family came and those are some things that really stick with me.

And yet, knowing that there was a pretty major effort that was still ahead of them to try to recover.

And then of course, as the days went on then people really started to look at that crop that was in the field and say, what are we going to do?

What do we have here?

And will we have to go harvest?

What is that going to look like?

And I also remember visiting with farmers who had then gone about harvesting or attempting to harvest those crops and going one direction at mile, mile and a half per hour in the combine, being really hard on equipment in that process and just grinding through a harvest that just wouldn't end.

It took forever.

♪♪ ♪♪ Justin Glisan: The serial derecho that moved through the state -- Dr. Justin Glisan is State Climatologist of Iowa.

As a trained meteorologist, Glisan is responsible for extrapolating details in weather data and providing the results to policymakers.

When August 10th began, Glisan and his colleagues from several states were in a meeting watching a small band of storms forming on the eastern edge of the Northern Plains.

They had no idea how the day was about to unfold.

Justin Glisan: In the forefront of my mind during August of 2020 was the drought that was occurring in West Central Iowa, D2, D3 conditions, drought that we hadn't seen since 2012.

And we're chatting as the Zoom is going on saying, I really want this line to stay together because the trajectory is basically west to east, it'll go through the drought region, we might get some significant rainfall.

This line is starting to expand and we're severe warned as it is crossing the border from Nebraska into Iowa.

It gets a little east of Carroll, Iowa right in the D3 region and it hits a very unstable, explosive atmosphere and the line intensifies rapidly.

But I had never seen clouds this dark and I had never seen it get so dark so rapidly.

(storm winds blowing) Justin Glisan: I've storm chased, I've been in severe weather events.

This was the first time that I had been very scared.

(storm winds blowing) The weather continued to intensify.

By the time the line of storms arrived in Marshalltown, wind speeds reached 90 miles per hour.

The storm spun off three tornadoes causing widespread damage to the Marshall County seat, surrounding farms and nearby small communities.

The straight-line wind storm began to feed warm air back into itself, increasing its strength and becoming a derecho.

(sirens sounding) State climatologists across the Midwest note, tornadoes, derechos and severe storms are changing.

They bring stronger, longer lasting wind gusts, heavier rains and record amounts of precipitation.

This unpredictability is increasing the difficulty for meteorologists to predict how storms will move across the countryside.

Glisan says, a derecho is now forecast to hit Iowa about every two years with the trend starting in 2012.

(storm winds blowing) But a storm producing the strength of the August 10, 2020 system is calculated as being a once in a decade event by the National Weather Service.

Justin Glisan: Now, aloft in this system we had warm air that allowed the updrafts to tilt backwards.

So, it was kind of a self-perpetuating line in that it couldn't shut itself off as a normal thunderstorm would.

You think of an updraft up, a downdraft down, that downdraft kills all the warm air going into the storm, the storm dies.

Well, with this derecho line it hit very unstable air.

As those downdrafts are coming down they're hitting the surface with such ferocity, it's pushing out cold air in front of it, it forces up warm air in front of that initial line, you get new towers that form as the old towers die behind it and that line is able to perpetuate 770 miles over 15 hours.

♪♪ As the storm system continued its march eastward, sustained wind speeds climbed to over 120 miles per hour.

(storm winds blowing) The derecho reached its peak as it entered Linn County.

Winds measuring the strength of a Category 3 hurricane pummeled Cedar Rapids and surrounding areas continuously for 45 minutes.

(storm winds blowing) The 133,000 people calling the county seat home were without power for two weeks and over 50% of the city's celebrated tree canopy was either damaged or destroyed.

Emma Hannigan: I saw in my own back yard how the trees were reacting and I knew something serious was happening.

I knew that we were going to have damage.

I did not know until a couple of days later the extent of the damage because there was no communication, especially in that Cedar Rapids, Linn County area where it was so heavy.

Emma Hannigan is the Urban and Community Forester with the Iowa Department of Natural Resources.

Hannigan recalls the magnitude of destruction brought on by the storm.

The devastation had her reaching out to forestry officials across the country for help in making sense of what had just hit the state.

Emma Hannigan: So, I was in contact with the U.S. Forest Service right away about the extent of what I knew and I also have coordinators throughout the country in other states and one of the things that I did was I reached out to areas that have hurricanes, that have large storms.

For example, I was in contact with New York and how they responded to Sandy and some of those responses to help me figure out what were my next steps.

Within a month, the Iowa Department of Natural Resources teamed up with the Maryland Department of Agriculture to begin aerial surveys in order to assess the damage to Iowa's forests.

The results of the survey showed the derecho had damaged or destroyed over 32,000 acres of urban canopy.

(chainsaw cutting through a tree) Additional data from the U.S. Forest Service estimated more than 4 million trees in the storm's path were either damaged or destroyed in the 2020 event.

Emma Hannigan: So, some places where we did rapid assessments had over 50% damage.

We did not measure over 50%.

That is going to take decades to restore that canopy.

It takes many, many years to establish a tree and the amount of planting that has to go into making our next forest is a lot of labor and intensive work to get them watered, to get them planted.

Rob Hogg: My home was affected in the derecho of 2020 on August 10, 2020.

And in Cedar Rapids it is, it's an ongoing disaster.

Rob Hogg is an author, attorney and former state Senator from Cedar Rapids.

In 2012, he introduced bipartisan legislation to help streamline disaster assistance across the state through the Flood Mitigation Act.

Rob Hogg: One of the things that has been so attractive about Cedar Rapids was the beautiful forests and trees in our city, a long-time commitment to trees and the canopy.

And you still see a few blue tarps, homeowners who just never, didn't have the insurance or didn't have the ability to get it together.

For me personally, it was a 16-month process to get my house put back together and that was with good insurance.

We're not here to plant trees, we are here to grow trees.

The city of Cedar Rapids has committed up to $1 million annually over the next decade for a massive urban replanting project.

The designers of this project have selected a variety of native trees they believe are genuinely able to stand up to extreme weather, disease and invasive species.

The Iowa legislature also allocated money for the Derecho Community Forestry Grant Program, which provides matching funds for communities to replant trees.

Hannigan believes the time it will take to fully rebuild the forests and plant new urban canopies will be measured not in years, but in generations.

Emma Hannigan: So, we have diversity in a lot of different ways.

One is through species diversity, which helps us with future impacts of pests and diseases, for example, like we have with Emerald Ash Borer.

But also, we like to have stands that have different ages so that when we lose mature trees, we have new trees coming up.

And that is really important to the health of urban forests.

As the new urban forests are being established, Iowans, from state foresters to city employees to regular citizens, will be on the lookout for trees weakened, but not destroyed, by the state's record wind event.

Emma Hannigan: And with those damaged trees there is a lot of secondary things that can happen.

And we know when there's wounds in trees that secondary pests can come in and also, we can have decay, which shortens the life of a tree.

That tree also may need more maintenance over time to keep it going as it deteriorates faster.

Another thing that we see with damaged trees is they don't provide as many benefits.

The August 10th storm left no doubt how much damage was done to the 2020 corn crop.

Before the derecho, the USDA Crop Conditions Report rated most of the state's corn crop in good shape and a week ahead of schedule.

But after the storm, the estimated corn yield for 2020 was reduced by 254 million bushels.

♪♪ Mike Naig: You knew it looked tough, you could look at a crop from the road and know that there was significant damage.

But when you got out and walked in fields and saw it.

But then it's another thing to try to go out and harvest it.

And again, the harvest is supposed to be this great time of year where you've put all of your effort and energy into this crop and now you get a chance to go out and see what it's like.

And frankly, there were some really good-looking crops in the parts of the state that were damaged heavily.

So, folks were excited about what this harvest season was going to bring.

♪♪ East of Marshalltown near Toledo, Iowa, farmers watched helplessly as a projected record crop was crushed in a matter of minutes.

Jacob Benda: Seeing all the corn just lying flat and it's just like, oh man.

I mean, I had seen that back in 2011 when that derecho came through.

That was in July.

And that corn actually goosenecked back up.

But with as late as this was, this corn was not, that plant was not growing anymore.

It was all focused on filling out that ear.

And I knew right away it's like, that's not going to be coming back.

We got declared zero on all but about 10% of our farm.

So, just shy of a hundred and some acres.

And so, we combined that, disked the rest all underneath and talk about a sick feeling in your stomach just disking up corn.

I never ever want to do that again.

(nature sounds) The magnitude of the August 10th derecho has made crop resiliency a top priority for many farmers.

In the aftermath of the event, some corn producers and seed companies noticed newer varieties of short-stature plants fared better than taller stalks.

Mike Naig: You think about, what does it take for a crop to be more resilient in the face of variable weather?

And so, absolutely.

I think farmers are interested in looking at those traits, again provided that they still achieve the same kind of yields that they're looking for, but I think breeders and seed companies are absolutely recognizing that we've got to look at this to, again, be more resilient in the face of whatever the weather throws at us into the future.

(traffic noise) Iowa is not alone in dealing with evolving weather patterns and storms pushing wind speeds higher and rainfall amounts to record levels.

(rain falling) ♪♪ In December of 2021, a severe line of storms produced an EF4 tornado in Mayfield, Kentucky.

The twister was part of a much larger system that stretched over six states.

The supercell thunderstorm spawned multiple tornadoes on its eight-hour, 350-mile journey through several Mid-Atlantic states.

♪♪ For Glisan, the significance of this storm wasn't just the system's severity, but the storm's timing.

Justin Glisan: Along that cold front, along that squall line and eventually what would become a derecho, by no means as devastating as the August 10th derecho, 63 tornadoes were spawned from that event.

We're talking the middle of December.

The largest tornado outbreak for December for the United States, in the United States' history, across Iowa, but also the largest outbreak of tornadoes for the state of Iowa for any month, in December.

It blows your mind.

It still blows my mind thinking about that.

(storm winds blowing) The conditions needed for storms to spawn multiple tornadoes, coupled with expanding and shifting storm fronts across the country, are among the conditions Glisan and other climatologists have been watching for several years.

Justin Glisan: The general summary there is we're seeing more outbreaks of tornadoes as opposed to one-off tornadic events.

We're also seeing some semblance of a shift from the classic Tornado Alley, which is in Nebraska, Oklahoma, down into Texas and expands into parts of Iowa, it depends on what your definition of Tornado Alley is.

We're seeing an increase in tornadoes in Dixie Alley, Kentucky, Tennessee, Alabama, Mississippi.

(chainsaw sounds) Extreme weather events have continued to plague the Hawkeye State.

In spring of 2022, a storm system composed of three supercell thunderstorms spawned 10 tornadoes.

The most powerful twister an EF4, touched the counties of Madison, Warren, Polk and Jasper, packing 170 mile per hour winds as it made its 70-mile trek across the center of the state.

Justin Glisan: In terms of weather across the state, it is becoming more extreme, it will continue to be extreme whether it is drought, heat waves, flooding, all those severe weather events are going to become more extreme.

Glisan believes that climate change is playing a role in the severe weather trend being experienced by Iowans over the past decade.

How much climate change may have influenced the conditions that launched the 2020 derecho may not have a simple answer.

Justin Glisan: So, when we talk about climate change impacting severe weather, winter weather, any kind of weather event that we talk about, we don't use one event to dictate a trend as a scientist.

We need multiple data points that tell us in a direction that we're moving.

Peer-reviewed studies that have shown that the days in which severe weather environments have increased, especially in March, April, May, April, May, June are due to a warmer climate.

So definitely there are climate change fingerprints on the larger scale structure of the atmosphere.

Now, for individual events, was the August 10th derecho supercharged because of climate change?

We don't know yet.

♪♪ For most, the physical damage to the buildings and the landscape will eventually disappear, becoming a distant memory.

For some, the emotional toll will always linger.

Mike Naig: I think the derecho of 2020 did wake a lot of folks up to say that this is something that, again, we had seen severe weather, we expect to have severe weather, but to see something of this magnitude, I do think it's got people thinking about what does the future hold for us?

♪♪ ♪♪ ♪♪ ♪♪ ♪♪ ♪♪ ♪♪ Funding for this program was provided by Friends, the Iowa PBS Foundation, as well as generations of families and friends who feel passionate about the programs they watch on Iowa PBS.

Funding for this program was provided by the Gilchrist Foundation, founded by Jocelyn Gilchrist, furthering the philanthropic interests of the Gilchrist family in wildlife and conservation, the arts and public broadcasting and disaster relief.

And by, the Claude P. Small, Kathryn Small Cousins and William Carl Cousins Fund at the Quad Cities Community Foundation to support nature programming on Iowa PBS.

♪♪ Support for this program has been provided by the Strickler family, in loving memory of Lois Strickler, to support programs that highlight the importance of Iowa's natural resources on Iowa PBS.