The scientists’ goal? Capture ultra-detailed radar scans from the inside of Laura, probing the tempest in a way that traditional Doppler radar simply couldn’t. The team was particularly interested in Laura’s eyewall, the unbroken ring of extreme winds and rain surrounding the storm’s eerily calm eye.
But getting into the core meant enduring the worst of Laura’s fury. Preparing for that was no easy task, but to scientists Josh Wurman and Karen Kosiba, tapping into this elusive data was worth sleepless nights and the perils of venturing into devastating winds topping 100 mph.
Probing violent whirlwinds that orbit the eye of the storm
Before setting out to intercept Hurricane Laura, Wurman let his objective be known.
“What would be ideal … the center of the eye would come over us,” explained Wurman. “We could have both radars in the eye at the same time. Then we would get this dual Doppler, have both radars triangulating … hopefully get some interesting features.”
Those “interesting features” aren’t just scientific curiosities. Understanding their dynamics has significant real-life applications, ranging from improving weather forecast models to strengthening and guiding building codes in hurricane-prone areas.
Kosiba said there were two main features the pair of scientists were on the hunt for — mesovortices and TSVs, or tornado-scale vortices.
Mesovortices are areas of low pressure, each a few miles across, that crowd inside a hurricane’s eye. Sometimes a storm may have four or five of them dancing around a common center. Mesovortices can bend and contort the inner edge of the eyewall, leading to extreme air pressure and wind fluctuations for those on the fringe.
TSVs, on the other hand, are much more localized.
“For the tornado-scale vortices, they’re about 500 or 600 meters across,” Kosiba said. While they’re not terribly strong on their own, TSVs can cause serious damage when added to the background of the already whipping winds in a hurricane.
“The thing with those is they’re embedded in the flow,” which has an additive effect when it comes to the winds, Kosiba explained.
For decades, atmospheric scientists had been aware of bizarre wind patterns believed to lurk in the core of extreme hurricanes, but efforts to observe them proved challenging.
Damage surveys in the wake of Hurricane Andrew in 1992 suggested their existence. But most of what was known about these odd eddies came from post-storm analysis of the damage, or low-resolution National Weather Service radar scans. That all changed when Kosiba and Wurman acquired an incredible data set from inside the core of Hurricane Harvey in 2017.
During Harvey, Kosiba was in the DOW when it was struck by a 146 mph wind gust, which the team later determined was from a TSV. Several nearby cars were lifted up, or even tossed into the remnants of a building.
Kosbia and Wurman weren’t sure what to expect this time from Hurricane Laura. But the intrepid duo was ready.
Dropping into position
Logistics were falling into place quite nicely early in the week. Then, when the team set out to put the DOWs into position for the storm, one caught on fire.
DOW 7, one of two Doppler on Wheels trucks, was stranded on the side of Highway 73, about 30 miles west of the team’s hotel. A clogged-up air filter had caused the engine to overheat, while battery issues had also fried several important wires.
“All of a sudden the lights went out and everything went dead … and I looked over out the window and there was all this smoke pouring up,” data technician Paul Robinson said. “There was glowing orange and sparks above the batteries.”
While three technicians were working to repair DOW 7, Kosiba and Wurman had ventured farther east in search of additional sites for deploying the DOWs. He pulled up a map of 30 or so dots scattered about the southeastern Texas and western Louisiana coastline that could work, depending on where the eye moved ashore.
Usually scouting out locations is relatively straightforward: The team plans to be someplace not vulnerable to the coastal storm surge or blown projectiles. But the forecasts of Laura’s 15- to 20-foot storm surge ruled out most of the team’s options.
Eventually, Kosiba and Wurman settled on two adjacent locations — a bridge over the Sabine River on Interstate 10 at the Texas-Louisiana border and a highway overpass in Toomey, about four miles to the east.
By midafternoon, showers in the humid air ahead of Laura were wafting across the Gulf Coast. After jerryrigging a short-fused repair to the battery problem for DOW 7, the three technicians began wrapping the radar dish mount in plastic wrap and duct tape. Drew Frambach, also a data technician, said doing so was necessary to prevent wind-driven rain from managing to penetrate into sensitive electronics.
By late afternoon, both DOWs were in their respective spots. Then it was time to settle in.
The doors close
At 8 p.m. Wednesday, the doors to DOW 8 closed, a ceremonious sealing off the outside world much like the feeling of boarding a long flight at the airport. The first drops of light rain sprinkled the windshield, while the soothing rhythm of the truck’s diesel engine competed with the drone of the air conditioning.
Wurman seized the opportunity to reminisce about his first time bringing a DOW into a hurricane during Hurricane Frances in 2004.
“We took it in. We had no idea if we could do it,” Wurman said with a smile. “The idea was, ‘Here’s this zone of death. Get out.’ And yet [we were going in]. We were pretty worried.”
Kosiba and Wurman have been chasing Mother Nature’s worst together for more than a decade. She joined Wurman after the two met while she was a PhD student at Purdue.
The two have had years of adventure together. They talked of experiences with vicious tornadoes and catastrophic hurricanes as casually as two office colleagues deciding where to order lunch. For them, the atmosphere’s full fury is just another day at work.
“Karen directed me into a tornado once,” Wurman said, laughing, as Kosiba smirked to herself. “Karen was telling me [the] tornado was in a certain place, and she was right. But on the laptop I was using, someone had switched to English units. It was a metric-English conversion error.”
About 9 p.m., both scientists settled into their perches, each in a safety vest seated in front of an eight-panel computer display. Graphs, radar plots and satellite imagery adorned the screens.
With a gentle but fresh breeze and light to moderate rain pelting against the windshield, one could have easily fallen asleep.
During mid-evening, energy was still high as final preparations were made. But once the radar started scanning, most of the work was done. Then it became a waiting game.
Wurman lowered his wire-rim glasses, reading off his phone professorially, and announced, “My dad just texted, ‘We’re going to bed.’ He said, ‘Text if you’re in trouble.’ ”
A moment of silence followed.
“I said, ‘If I’m in trouble, I’ll be swimming and bleeding,’ ” he said with a laugh. “Not texting.”
Kosiba described the pace of work as a “slow burn.” Already up for more than 18 hours after working long days Monday and Tuesday, the scientists would be on duty for at least another 18 to 24 more.
The eyewall arrives
With the DOW’s radar scanning and successfully logging data, Wurman glanced at the local National Weather Service’s data feed about 11 p.m. to gauge the position of the storm. The mood became a bit more subdued as it became apparent the eye might miss the team’s radars to the east.
“If I had to guess, I’d say the actual center will pass 10 miles east or so,” said Wurman without taking his eyes off the screen. “If it passes five to 10 miles east, then we’re still in the eye.”
Kosiba smiled solemnly.
“I’m not feeling it,” she said.
The rain picked up in intensity outside, arriving in sheets as the winds gently rocked the 12-ton DOW back-and-forth. By midnight, the northwestern edge of the eyewall was scraping the Texas-Louisiana border. Before long, the gentle swaying of the DOW felt more like the vehicle was being targeted by battering rams.
Then the eyewall hit.
DOW 8 rocked like an aircraft in severe turbulence. Gusts of wind between 100 and 110 mph shook the vehicle. It seemed like any minute it would be lifted — yet both scientists sat calmly reclined, their demeanor more reminiscent of a quiet living room.
Farther to the east, the community of Hackberry had been swallowed into the eye.
“Hackberry was our favorite site,” muttered Wurman. “The site’s probably underwater though. That’s the problem.”
A 106 mph wind gust rocked the vehicle.
“This [wind] is kind of what you would expect, if you’re just skimming the western eyewall,” explained Wurman, moments after the automated anemometer on a mast atop the DOW registered a 111 mph wind gust.
The wind screamed outside as the windshield displayed a scene like the inside of a carwash.
About 3 a.m., the wind was still fierce — yet Wurman was briefly dozing. Until it began raining on his face.
A leak had formed somewhere on the windward side of the vehicle, and the pressure-washer wind and rain had found their way inside. Kosiba and Wurman jumped into action to patch it with duct tape before it could damage any electronics. The truck, meanwhile, was jostling like a ship in rough seas.
Suddenly, a pair of headlights appeared in the middle of the darkness on the opposite end of the bridge. The lights grew brighter until a hulking figure emerged out of the darkness — it was a semi tractor-trailer, fishtailing in the extreme winds, on a collision course with the DOW. Everyone instinctively ducked.
At the last minute, the driver stopped short of the DOW.
Fearing someone in the cab might be facing a medical emergency, Wurman donned a raincoat and ran out into the storm. Five minutes later, he was back.
“The driver is looking for Alabama,” he said.
Onto the next storm
About 3:30 a.m., the winds began to die down. Everyone inside DOW 8 began to drift to sleep.
When daylight dawned two hours later, it was time to pack up.
“I think the data looked great,” Kosiba said. “I feel really good about that. We got nine hours of dual Doppler radar.”
“I am actually happy with our location at the edge of the eye,” he said. He explained that maximized the time spent in the eyewall.
But there was still a sense of wondering what could have been. After a moment, Kosiba spoke up.
“I still wish we were in the eye.”
Wurman and Kosiba began disassembling equipment and moving suitcases and bags of supplies.
“We usually try to get out pretty fast,” Wurman said. “If there’s high level winds here and wind damage, we might stay and damage survey. But there’s no power, no hotels. … We just want to get out … of the disaster area as quickly as possible. In this case, going to Houston is pretty good.”
By 8 a.m., the DOWs were a pair of fading taillights, driving off until the next storm.