On May 28, his team captured jaw-dropping video of a beastly tornado tearing along near Tipton, Kan. The twister was flanked by storm chasers Skip Talbot, Jennifer Brindley Ubl and Hank Schyma. Each had a camera trained on the funnel as its multiple vortices dangled over open fields. Before long, the menacing tornado clipped several structures — tossing debris hundreds of feet into the air.
Their images are beautiful, captivating and terrifying. But more than anything, they’re scientific. That’s where Seimon’s project comes in.
His aim? Return to the basics, employing photogrammetry to estimate tornadic wind speeds. It’s a technique that involves analyzing adjacent video frames to deduce wind speeds from debris motions.
By considering videos of a tornado shot from multiple locations, Seimon can track from several angles the objects entrained in its circulation. That allows him to mathematically derive wind speeds with relatively high precision.
“We’re not inventing anything new,” Seimon said. “But it’s sort of a lost art.”
In the age of mobile Doppler radar units and chasers stalking tornadoes from every angle, it’s hard to believe secrets could still elude, but they do. “Radars, by nature, can’t scan down low enough where it really counts,” Seimon said. “We don’t actually know much about how tornadoes interact with the surface.”
The tornado research of Ted Fujita, a University of Chicago scientist, in the 1970s relied heavily on photogrammetry. At the time, the results were groundbreaking. Since then, the technique has largely been shelved, abandoned for more technologically complex methods of observation. But with the advent of 4K camera technology and its mainstream availability, there has been a resurgence in photogrammetry’s appeal.
“In the past, photogrammetry could only be performed on individual pieces of debris,” Seimon said. “The problem is that tracking a large object tells us very little about the wind propelling it.”
Now, relatively inexpensive 4K cameras with significantly higher resolution allow one to focus on individual billows of dust or turrets of water vapor at the base of the funnel.
If you’ve had a picnic on a breezy day, you’ve experienced this effect. Your napkins, paper plates and other lightweight objects were probably swept up in the breeze and carried, but your car wasn’t tossed about by winds (hopefully). Smaller, lighter objects are far more susceptible to movement and are much better indicators of wind speed.
“Smaller tracers are much less subject to centrifuging and other frictional effects,” Seimon said. “One can find much finer airborne details. We can really map those winds near the surface.”
Surrounding a tornado with a slew of 4K cameras is a massive undertaking. That’s why Seimon has enlisted the help of professionals.
“The objective is to have at least three teams on one storm in a coordinated fashion for multiple perspectives,” he said.
His work builds on previous projects funded by National Geographic in the early 2000s, spearheaded by legendary tornado researcher Tim Samaras. The project was revisited in 2013 after a massive tornado in El Reno, Okla. — the same storm that claimed Samaras’s life.
In the wake of the tragedy, Seimon kept the legacy of Samaras’s work alive. The data collected in the El Reno storm afforded the perfect opportunity to learn.
“There was so much high-quality video that we were able to develop some new methodologies,” Seimon said. “We geolocated storm-chase video through Google Maps, used lightning flashes to precisely time-synchronize it and built on a number of other resources.”
Since then, Seimon has been hoping for a day like the team had on May 28. It’s been years in the making.
“Our project’s chasing goals were finally realized with a full team, close-range intercept‚” Talbot wrote, happy that the team’s efforts paid off. “We’ve got the perfect mix of academic meteorology, techno geek skills and artistic mastery of capturing the chase.”
Looking back on last month’s chase, Brindley Ubl agreed: “It’s been the culmination of years of dedication and hard work.”
At one point, three tornadoes were on the ground simultaneously, with the group targeting the most intense of the trio. As the tornado barreled toward a clustering of buildings, “Pecos Hank” Schyma can be heard saying, “Looks like the homestead is going to take a direct hit.”
In the end, despite some damage, nobody was hurt by the tornado, which at times was more than a half-mile wide. Instead, it left behind an incredible data set.
What secrets does the data contain? Only time will tell.