Moments before a massive tornado would wreak havoc on their community, destroying hundreds of homes and killing nine residents, almost no one in the small town of Parkersburg, Iowa, had any idea what was about to hit them.
But with conditions that seemed just right for a tornado, storm-spotters like Ben McMillan were out surveying the Iowa countryside. During tornado season, storm spotters are often deployed to monitor bad weather as it rolls in.
McMillan is a member of Central Iowa Skywarn, a volunteer organization that partners with the National Weather Service (NWS) to track storm conditions and issue tornado warnings around the state.
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On the afternoon of May 25, 2008 -- the Sunday of Memorial Day weekend -- McMillan was on a storm-spotting mission near Parkersburg when a dangerous mix of meteorological forces began to coalesce just outside the town of 1,900 residents.
"[The National Weather Service] issued a tornado watch called a PDS tornado watch, or a 'particularly dangerous situation," McMillan said. "When you see the words PDS or hear the words 'particularly dangerous situation,' watch out, because that's something that's pretty rare."
Initially, the storm spotters honed in on area to the west of the town. "One of our initial targets was the city of Ackley, which is just to the west … and we had a large storm cloud go up right over the city of Ackley. And, at that point, we felt that that was going to be a potential candidate to become a very violent storm," he told ABC News' Sam Champion.
"I just seem to have a knack for being places when stuff happens," McMillan said. "I've seen a lot of major tornados over the past 10 years."
Click here to watch McMillan's video of the tornado brewing.
"The earth was releasing so much built-up pressure in this case, that it just -- formed more rapidly than a storm I'd ever seen before. Most tornadoes, it's a process -- this was on steroids. It was so violent, so quickly it went from nothing to the most violent tornado on earth. This was like an atom bomb going off," he said.
Eyewitness: 'This Was Just a Massive Black Cloud of Death'
Not only was the pace of the storm unlike anything McMillan had ever seen, so was its appearance. "The storm wasn't your classic tornado; it wasn't a little ropey thing that came down," he said. "This was just a massive black cloud of death."
Meanwhile, Chief Deputy Tim Wolthoff of neighboring Grundy County was also on duty that day, patrolling the area for storms with his 20-year-old son.
Here in "Tornado Alley," storm spotting is just another part of the job. "We're out there to protect and to serve and that's part of our job is to go out there and, you know, protect the community if at all possible," Wolthoff said.
Wolthoff was sent to track storms in the northern part of Grundy County, south of Parkersburg. "As we got further north, then you could see that it was starting to get pretty dark," he said.
Minutes later, Wolthoff heard reports over the radio that the tornado had stuck ground and, almost instantly, he saw the storm with his own eyes.
"That's when we saw this huge tornado ... the biggest one I've ever seen in my lifetime," he said. "My son and I both said, 'Wow, this is huge.' It was moving extremely fast. You could definitely tell it was heading right towards Parkersburg."
Like McMillan, Wolthoff was shocked at both the appearance and the size of the tornado. "It was not like your normal tornado funnel cloud that you would normally see photos of or on TV. This was just a huge, looked like a massive cloud that was rotating," he said.
McMillan, as well as other storm spotters, alerted local authorities, who directed the fire department to set off tornado sirens. Fatefully, the town had installed a second siren a few days earlier in the part of town near the tornado's path.
"It actually was practiced with, the day before our tornado hit," Parkersburg Police chief Chris Luhring said. "They practiced initiating that siren on Saturday, less than 48 hours before our tornado hit."
Meanwhile, with first responders already on alert, Wolthoff monitored the storm's movement and captured it on video.
By this point, there is nothing that the people of Parkersburg can do but take cover. In fact, people had just 8 minutes after the sirens started blaring until the tornado hit.
Parkersburg Hit by the Strongest, Most Dangerous Kind of Tornado: An EF5
The pace of the tornado, as well as vigilant first-responders, was breathtaking. The first tornado touched down at 4:47 p.m., east of the town of Ackley. At 4:51 p.m., Parkersburg's tornado sirens began to wail. At 4:59, the tornado hit Parkersburg.
"There was only a very small window for people to recognize how strong of a storm this was and take appropriate action," McMillan said.
As terrifying as it looked, the brute force of the storm was even worse. Parkersburg was struck by the strongest and most dangerous type of tornado, known as an EF5. For earthquakes, there's a 10 on the Richter Scale and for hurricanes, there's a Category Five. When it comes to tornadoes, an EF5 is, quite simply, as bad as it gets.
"We're talking serious winds, stronger than Hurricane Katrina, 200-plus, mile-an-hour winds," McMillan said. "As spotters, it blew us away, we knew [an EF5] could happen. We didn't realize it could happen that fast."
The unbelievable force of the Parkersburg tornado, which grew to be three miles wide and cut a 40-mile path of destruction through Iowa's plains, leveled more than 250 homes and erased more than 20 businesses.
Perhaps most remarkable, though, is that relatively few people were killed. With damage like this, the toll could have been massive, but only nine people died.
McMillan remembers the feeling of dread that washed over him after the tornado passed.
"You thought that everyone had died," he said. "We thought hundreds of fatalities at first. We thought … no one had made it through that tornado in that damage zone."
As he and his fellow storm spotters rode into town after the storm, their fear grew as they anticipated a high number of casualties. "If they didn't get out of the way of the storm, they weren't going to make it through," McMillan said. "This is, truly, a storm that no one wants to ever face in person."
Massive Tornado Levels Hundreds of Buildings but Death Toll Is Low
The destruction throughout the town was even worse than he expected. "It was unrecognizable," he said. "I mean, this was wiped clean, foundations knocked off their, their base -- cars flipped, people -- not knowing what was left from right. I was scared to death."
Chief deputy Wolthoff, who immediately starting searching for survivors in the storm's aftermath, had a similar response to the wreckage.
"It felt like I was in a landfill," he said. "Everything was just destroyed. … My main concern at that point was the loss of life. You didn't know what was what. … It was just heart-wrenching."
Wolthoff credits the low fatality rate to a number of factors: the holiday weekend meant many people were out of town and the tight-knit community responded quickly to the tornado sirens.
Ultimately, though, he thinks it was a miracle. "The good Lord was on our side," he said.