Iowa Alumni Magazine | February 2001 | Features

The Iceman Cometh

By Tina Owen

When winter winds howl and ice storms slink across Iowa, most people shudder at the thought of the freezing weather. Not Wilfrid “Wilf” Nixon: snow and ice make his day. “I admit it—I love it when it's snowy and icy. I monitor the weather stations, looking for blizzards!” he says.

His interest is professional, though, and it's paying off for people whose journeys on icy winter roads are becoming safer thanks to Nixon's work. Nixon is a professor and research engineer in the UI's Department of Civil and Environmental Engineering and the Iowa Institute of Hydraulic Research. Renowned internationally for its work in the field of ice and snow, the University of Iowa is one of the two leading winter maintenance research establishments in the U.S. (The University of Utah is the other.) For the past ten years, Nixon's research has focused on improving the winter road maintenance programs carried out by the Department of Transportation (DOT), county engineers, and city workers.

UI engineering professor and ice expert Wilf Nixon hails from England, but he loves Iowa's freezing winters and the work that takes him to some of the world's coldest regions. “I love it when it's snowy and icy. I monitor the weather stations, looking for blizzards!” he says.

Frozen Iowa seems a strange choice for someone who hails from a part of England that barely sees enough snow and ice each winter to scrape together a single snowball. Growing up in Harpenden, 30 miles north of London, Nixon says the only substantial snow he can recall was in 1963, when “my one-eyed aunt came for Christmas, stayed till Easter, and lost her boot in the snow. I was four at the time, and winters afterwards seemed pale and dreary in comparison.” Reflecting on how he arrived at Iowa, Nixon recalls lines from “The Road Not Taken” by Robert Frost. “Two roads diverged in a wood, and I—/I took the one less traveled by,/ And that has made all the difference.” As a 15-year-old schoolboy studying the poem, Nixon knew that those words resonated within him. But he never dreamed that he, too, would eventually step out on a road less traveled—an icy one that would lead him all the way to the University of Iowa.

Nixon found himself having to choose between two paths in 1981 when he considered which doctoral thesis topic to pursue at Cambridge University, England. The old joke about PhDs says that you learn more and more about less and less until you know absolutely everything about nothing at all. Not wanting to fall into that trap, Nixon passed up a “very vanilla” project to investigate how aluminum—“aluminium,” he corrects, with a laugh—behaves under loading pressure. Finding his imagination engaged more by a block of ice than a block of “aluminium,” he opted instead for a project that aimed to solve the mystery of why glaciers behave as they do.

After Nixon gained his PhD in engineering from Cambridge in 1984, Dartmouth College in Hanover, New Hampshire, offered him a year's postdoctoral research fellowship. That evolved into a further two years as a visiting assistant professor working closely with the U.S. Army Cold Regions Research and Engineering Lab. Then came a phone call from Rob Ettema, former associate director of the Iowa Institute of Hydraulic Research, asking if Nixon would be interested in helping address the problem of ice on the Mississippi.

That's how Nixon and his English wife, Katherine, found themselves unloading a U-Haul truck in Iowa City in the summer of 1987. The temperature was above 100 degrees, and Nixon remembers thinking that it was “way, way, way too hot”—especially for someone who planned to study ice. Thirteen years later, Nixon has adjusted to Iowa summers—although he still dislikes the thunderstorms that knock out power to the ice labs in the East Annex where many of his experiments are conducted.

He's also acclimatized to the Iowa winters. He counts himself fortunate that he's managed to avoid a car accident on the icy roads, although he's fallen “on his bum” several times on frozen sidewalks. While working at Dartmouth College, he once traveled to the Arctic and camped out on a frozen sea. “It was pretty cold,” he says in his understated British way. “But I've been in much colder weather here in Iowa.”

Sitting in his large, sparsely furnished office in the new Seamans Center for the Engineering Arts and Sciences, Nixon rummages around in bulging files and digs out photos of bright blue glaciers, red snowplows, and steely gray ice labs. He unveils the colorful secrets of those labs, his calm, quiet voice making the bizarre sound perfectly commonplace. The ice labs consist of five rooms capable of operating at temperatures as low as -45 degrees centigrade (-49 fahrenheit). Each year, Nixon grows and harvests ice, like a living crop, to be used in a variety of experiments.

To grow a particular type of columnar ice, he chills the ice towing tank to just below freezing point, then “seeds” it by spraying a fine mist of water over the surface. When the ice is about eight inches thick, Nixon and his colleagues harvest it by cutting the ice sheet into blocks with chainsaws. In some experiments, blocks of ice are subjected to loads up to 100,000 pounds to see where they stress and fracture. “Sacrificial” ice is carefully placed so that it evaporates rather than the main block being investigated. In the towing tanks, scale models are made to examine how ice interacts with structures like bridges. To achieve the correct scale of thickness, the ice is doped with urea to make it thinner and weaker.

“The idea is that the results you get in the laboratory will then reflect what happens in the real world,“ Nixon explains. And it's the needs of the real world, not simply the esoteric knowledge found in laboratories, that seem to drive him. Nixon chose to investigate ice for his doctoral thesis because he wanted to apply his knowledge in ways that would be of practical use to others. That quest for useful knowledge has taken him as far as the Arctic—and as close as Coralville.

Nixon “As long as people are still driving on roads, there will always be the need to remove snow and ice from those roads. What will change is our ability to know what's out there on the road ahead,” says UI engineering professor Wilf Nixon.

In the winter of 1990, Nixon could be found driving around the frozen Coralville reservoir spillway on a borrowed snowplow. Working with the Iowa DOT and the federal Strategic Highway Research Program, he was trying to find the most effective way to set up the underbody plow blades so that they removed the most ice in one single pass.

"The idea is to remove as much ice mechanically as possible so you can reduce the amount of salt or other chemicals you put down,” he explains. “That's good news because those chemicals cost money and have an effect on cars, roads, and the environment.”

Snowplows trundling along the roads during Iowa winters are a familiar sight, but probably few people would suspect the level of technical skill required to operate them effectively. Operators pull on levers that use hydraulic pressure to lift or lower the blades mounted on the underbody of the plow. Set low, the blades wear down quickly; too high and they don't remove enough ice. For many years, adjusting the level of the blades correctly came down simply to operator skill. But with many experienced snowplow operators due for retirement, the DOT needed a more scientific approach.

“Experienced operators used their buttocks to gauge just how the blades were set,” explains Nixon, with such a tongue-in-cheek expression on his face that for a second it's impossible to tell whether this is another example of his dry sense of humor. “Seriously,” he goes on, “they tapped on the right-hand lever until their right buttock cheek came up off the seat, then tapped on the other lever until their left cheek came up. You can imagine that this is probably not something you want in a training program, particularly if you're looking to acquire a more diverse workforce—the opportunities for misunderstanding would multiply. So we were aiming to come up with ways of setting the hydraulic pressure that didn't rely on well-calibrated buttock cheeks.”

Nixon was also trying to take some of the pressure off snowplow operators. “They're out there doing a difficult job, trying to keep the plow on slippery roads in bad weather conditions while they put down the correct amount of chemicals. It's easy for them to become overloaded. We were trying to make it as straightforward as possible for the operator to run the truck, get the job done, and get back home without in any way compromising safety. Safety is absolutely paramount.”

photo of an Iowa snow plow Operating a snowplow is a technically difficult job. Thanks to the expertise of UI faculty, this tough task has become easier.

After ten years of research, Nixon came up with guidelines for the optimum amount of pressure and angle of blades and devised a system that allowed the blades to be set automatically at the press of a button. Those experiments led to his current work—the wider issue of how to get relevant information about winter weather to the people who need it. Information is the key to making the best use of the improved technology—such as anti-icing chemicals—now available. The U.S. spends $1.5 billion a year on winter road maintenance. Iowa spends $35 million annually. Indirect costs—such as accidents, lost working days, stalled interstate commerce—cost the U.S. another $5 billion. “If a severe winter storm shuts down the interstates in Iowa, it'll probably cost the state about $600 million a day in lost revenue and work,” says Nixon.

Still at the concept stage, Nixon's latest project—cars communicating with each other and central computers to pass on road condition and weather warnings—sounds like science fiction. But Nixon is convinced that within five years, it'll be science fact. “We already have this technology—fuzzy logic and neural networks are in washing machines and supermarket scanners right now,” he says. “Global positioning systems and two-way broadband communications are installed in many vehicles, so it's possible for a computer to know where your car is and what hazards are ahead, and then send a warning message to your car.”

Nixon has identified three stages for getting the right information to the right people at the right time. Data, such as road surface temperature readings, is transformed into the information that it's below the freezing point along I-80. Then, delivered to a person approaching that section of the interstate, it becomes the vital knowledge that I-80 is icy and potentially dangerous.

" From my viewpoint as an engineer, the key issue is helping people travel on the roads safely,” Nixon says. “Winter weather is the challenge—whether you tackle it by improving the way snowplows operate or the kind of chemicals you put down on the roads, or by sending a message via someone's car radio warning of an icy bridge ahead. As long as people are still driving on roads, there will always be the need to remove snow and ice from those roads. What will change is our ability to know what's out there on the road ahead.”

Forward-thinking, groundbreaking work like that has earned the UI its international reputation in the sphere of winter road maintenance. Nixon chairs the Transportation Research Board's key national committee on winter maintenance. Four years ago, he set up an e-mail listserv that now includes more than 400 members from the snow and ice community around the world.

"It's a very useful tool for sharing information and experience,” he says. “And the e-mail address for the listserv contains '' so there are more than 400 people around the world who know that the UI is the place to learn about snow and ice. That's a very strong message we're sending out.”

Cool Stuff

The Iowa Department of Transportation (DOT) is increasingly turning to high-tech equipment and processes in the perennial battle to help make roads safer in winter weather. Non-conventional processes like these help reduce winter maintenance costs, improve travel conditions, and protect the environment:

Road Weather Information Systems (RWIS)
RWIS units, installed at 50 locations in Iowa, capture real-time data from a network of sensors imbedded in roadways and bridge decks. They provide information to a central computer about the temperature of the pavement, whether it's wet or dry, and how much deicing chemical is on it. Information about the surface freezing point and the subsurface temperature is also fed back to DOT maintenance managers so they can deploy materials, crews, and equipment at the right time and in the right place.

Data Transmission Network (DTN) Weather Centers
DTN weather centers located in 131 DOT maintenance facilities throughout the state deliver up-to-date satellite and radar images, current weather conditions, and forecast information so that maintenance employees can better plan and deal with winter storms. Another 38 units in interstate rest areas provide weather information to travelers.

Since 1993, the DOT has been testing and using an anti-icing technique on selected urban and interstate areas in Iowa. Liquid deicing materials are applied to the road immediately before or at the beginning of a storm (hence the importance of accurate weather information). Chemicals prevent or weaken the bond of ice to the pavement, so the road stays wet or slushy rather than icy.