National Geographic features UAH Ph.D. candidate’s research in thundersnow

Sebastian Harkema
Sebastian Harkema is a PhD candidate with UAH’s Department of Atmospheric & Earth Sciences studying thundersnow.
Courtesy Sebastian Harkema

Growing up in the snowy winters of Michigan, Sebastian Harkema, a Ph.D. candidate student in The University of Alabama in Huntsville’s (UAH) department of Atmospheric & Earth Science, still remembers the first time he heard the roar of thunder during a winter storm.

While it was a rare and exciting phenomenon to witness, Harkema would’ve never guessed years later he’d be featured by National Geographic as a leader in thundersnow research while in graduate school at UAH, a part of The University of Alabama system.

“It’s quite an honor to be featured by National Geographic. Their yellow rectangle border is iconic. When you see it, you know you’re going to be reading about the latest advances in scientific research,” says Harkema.

For decades, scientists believed electrification within snowstorms was caused by collisions between ice crystals and graupel, also known as a snow pellet, in the presence of supercooled liquid water.

The doctoral student’s research, funded by the Future Investigators in NASA Earth and Space Science and Technology (FINESST) program, found that graupel may not play as large a role in the electrification of wintertime stratiform events, such as nor’easters, as previously thought.

Harkema also found that when thundersnow occurs, the lightning associated with the wintertime event produces large, less frequent flashes.

“This is key to promoting lightning safety during thundersnow events. Large, less frequent flashes along with snow dampening the sound of thunder could pose a risk to society outdoors, who are unaware that thundersnow is occurring during a snowstorm,” says Harkema.

Harkema has made significant contributions in thundersnow research during his graduate studies at UAH. He has written and co-authored a number of publications and presented his research at several conferences, winning various accolades in recognition of his work. Most recently, Harkema presented his research on the Inhibition of Large-Scale Electrification Within Wintertime Stratiform Regions at the 2023 American Meteorological Society Conference, receiving high praise from colleagues within his field.

With all his success, it’s hard to imagine that his initial plan for graduate school never involved researching thundersnow.

Harkema was originally interested in UAH’s Department of Atmospheric & Earth Sciences due to its strong focus in satellite and remote sensing. Shortly after applying to UAH, research opportunities became endless for him.

Harkema was first contacted for an opportunity to work on a winter weather project through UAH Earth System Science Center’s cooperative agreement with NASA’s Short-term Prediction and Transition Center (SPoRT) for his graduate studies.

Wanting to take advantage of other research opportunities for students in winter weather, Harkema was encouraged by his NASA SPoRT mentor Dr. Emily Berndt and NASA SPoRT’s Dr. Christopher Schultz to apply to NASA’s 2020 Investigations of Microphysics and Precipitation for Atlantic Coast Threatening Snowstorms (IMPACTS) field campaign. It was there, where Harkema was given his first opportunity to study electrification with winter storms using aircraft observations.

After the field campaign, the doctoral candidate realized he wanted to research thundersnow for his Ph.D. dissertation. By taking UAH’s Department of Atmospheric & Earth Sciences Professional Development course, Harkema learned about NASA’s FINESST program. Guided by his UAH advisor, Dr. John Mecikalski, Harkema applied and received funding to fund his research to analyze how the electrification process works in stratiform wintertime storms.

Harkema is planning to defend his Ph.D. on thundersnow this spring. Post-graduation, he hopes to continue researching thundersnow and broaden his research to study electrification in summertime stratiform events.