This entry is part 6 of 22 in the series Winter - 2017

C3LOUD-Ex gives scientists a closer look for more accurate predictions

by Anne Manning

A darkening sky. A swirl of clouds. That rushing wall of cold, dense air. A looming thunderstorm is familiar, ominous theater.

Every day, atmospheric scientists pore over computer models to predict the where, when, and how of threatening storms – particularly those bringing strong winds, hail, and heavy rain. But even the best models fall short, in terms of by-the-minute forecasting that can save lives.

Colorado State University atmospheric scientists are pushing the boundaries of meteorological observation in an unprecedented attempt to fill critical gaps in storm prediction – made all the more pressing by the advent of climate change.

These CSU experts are focused on a solution – saving lives by developing more accurate storm prediction tools – and they’re exploring outside-the-box steps to get closer to that solution. That’s design thinking – and it turns out atmospheric scientists use it too.   

Armed with drones, weather balloons, and a healthy sense of adventure, scientists led by Susan van den Heever, associate professor of atmospheric science in the Walter Scott, Jr. College of Engineering, are peering into storm clouds as they form, in a manner never done before. Their goal: bolster prediction models with cutting-edge observational data and, ultimately, provide a clear picture of exactly how storms gather their strength.

Send in the drones

Van den Heever’s research project is called C³LOUD-Ex (CSU Convective CLoud Outflows and UpDrafts Experiment), and its results could one day change how forecasters call the play-by-play of storms. C³LOUD-Ex is supported by van den Heever’s Monfort Professorship. The Monfort Family Foundation-supported University program provides funding to two professors selected each year so they can pursue research and teaching projects that push the boundaries of traditional disciplines. Monfort Professors are encouraged to pursue innovative, outside-the-box creative design thinking.

During Summer 2016, van den Heever led a team drawing from four research groups across the Department of Atmospheric Science to complete Phase I of C³LOUD-Ex. It was a dry run of the primary eight-week field campaign, slated to take place in Spring 2017 during peak storm season in Northeastern Colorado and Southern Wyoming.

At the heart of C³LOUD-Ex is a forward-thinking exploitation of emerging technologies, including unmanned aerial systems, better known as drones.

Updrafts and cold pools

The purpose of C³LOUD-Ex is to understand two key aspects of thunderstorms: The fast-rising cores of air that shoot upward through storms, called updrafts; and the resultant bursts of cold air that rush back down to Earth, called cold pools (the wall of cool, dense, windy air you feel as a storm rolls by).

Updrafts can stretch more than 10 miles above the Earth’s surface; rising as fast as 60 meters per second, they can tear planes to pieces.

“We do not capture these motions very well in our models,” van den Heever said. “We don’t know from observations how strong the updrafts are, because we can’t fly through such severe storms. So, we are looking at novel ways, from the ground, of making measurements.”

Cold pools are also key components to sustained storms, van den Heever said. The stronger the cold pool, the longer-lived and more intense the storm.

Drone infographic

Straight into updrafts

The C³LOUD-Ex team is pioneering the use of GPS-tracked weather balloons to sample conditions inside updrafts. Weather balloons are usually used in clear air, not in the middle of a torrential storm.

Throughout the summer field campaign, the C³LOUD-Ex balloon team worked out how to guide balloons into updrafts – no easy feat. Lightning or strong winds sent many popped balloons careening back to Earth. With no instruction manual, the researchers were forced to improve their techniques through trial and error.

“We found that when we launched the balloon within the cold pool, the balloon was more likely to rise closer to the center of the updraft,” said graduate student Peter Marinescu. “This also helped us better understand the vertical structure of the cold pool.”

Fly into the eye

For their in-depth look at cold pools, the researchers turned to drones to make flights that humans can’t. The drones were outfitted with temperature, moisture, and pressure sensors, as well as visible and infrared cameras that captured breathtaking video. Taking data at one-second intervals, the drones also provided horizontal information inside cold pools, supplementing the single, vertical profiles the weather balloons provided.

“We can also sample near a storm, to get a feel for the atmosphere around a cold pool,” said graduate student Sean Freeman. The team’s overall technical lead, Freeman received Federal Aviation Administration clearance to fly the research drones.


Managing the complex daily operations of C³LOUD-Ex Phase I was graduate student Leah Grant. She also worked with Pat Kennedy of the CSU-CHILL National Weather Radar Facility to develop radar-scanning strategies – an important part of C³LOUD-Ex.

“Communication is a big component to the success of a project of this scale,” Grant said. “We had people running the operation center, overseeing overall decisions, and making sure people were safe in their vehicles.”

The C³LOUD-Ex spring campaign will involve about 20 students from numerous groups in the Department of Atmospheric Science.

“Our goal is to help people threatened by severe weather, and to ultimately improve the numerical computer models we use on a day-to-day basis,” van den Heever said.

C3LOUD-Ex Field Campaign

C3LOUD-Ex, the CSU Convective Cloud Outflows and UpDrafts Experiment is a CSU Monfort-Funded field project. C3LOUD-Ex phase 1 took place in July 2016. Phase 2 is planned to begin in April 2017.

The 2016 Team Behind the Storm

The 2016 team behind the storm

C3LOUD-Ex is a lean, mean, interdisciplinary team. Here’s a breakdown of who’s who.

Susan van den Heever
Principal investigator, associate professor in Atmospheric Science, Monfort Professor

Leah Grant
Project manager, Ph.D. student in van den Heever group

Sean Freeman
Technical manager, M.S. student in van den Heever group

Peter Marinescu
Operations manager, Ph.D. student, van den Heever and Sonia Kreidenweis’ groups

Julie Barnum
M.S. student in Steve Rutledge group

Emily Riley Dellaripa
Postdoctoral fellow in Eric Maloney and van den Heever groups

Aryeh Drager
Ph.D. student, van den Heever group

Greg Herman
Ph.D. student, Russ Schumacher group

Stacey Hitchcock
Ph.D. student, Schumacher group

Erik Nielsen
Ph.D. student, Schumacher group

Jungmin (Minnie) Park
Ph.D. student, van den Heever group

Chris Slocum
Ph.D. student, Wayne Schubert group

Ben Toms
M.S. student, van den Heever group