Storm-Chasing Doctor Makes Annual Trip to ‘Tornado Alley’

Colorado hospitalist Jason Persoff, MD, uses plenty of technology when he chases storms in hopes of seeing a tornado.

He checks sophisticated forecasting models and uses a high-quality radar app.

But at a certain point, when he’s in the presence of a supercell thunderstorm — the kind most likely to spawn a tornado — the technology goes away, and he relies on decades of experience to help him predict what will happen next.

“There’s a lot a storm can tell us, and they have a feel to them,” Persoff told MedPage Today. “It’s not dissimilar to how I can feel, when talking to a patient about a disease, where things are going.”

For about 2 weeks each year, Persoff takes a “vacation” from the hospital and joins a group of friends — meteorologists and other “adventure folk” — to chase storms. The last 2 weeks of May are usually the busiest in the U.S.’s “tornado alley,” which runs from northern Texas to South Dakota. The result is stunning photography, which he hopes instills in others the same sense of awe and wonder that he gets from witnessing some of the most impressive displays of mother nature’s power.

“It’s very difficult to realize just how big these storms are,” he said. “To see this incredible volume of air moving the way it is, it’s staggering, truly epic.”

Thrill of the Chase

A day or two ahead of their planned time off, Persoff and his storm-chasing crew will check the modeling to make their best educated guess as to where they should go to witness a storm. That usually narrows things down to a region or state, he said.

Since he lives in Aurora, Colorado (and works at the University of Colorado Anschutz there), he usually drives to the location.

“Mother nature is pretty fickle so even with the best laid plans, it’s not uncommon for us to find out that, a week or two before any of us are free, there’s a big tornado outbreak, and then it will be quiet,” he said. “Then some years we hit it out of the park. It’s just variable.”

They’ve traveled as far north as North Dakota, and all the way down to the Mexican border to chase storms.

On chase day, they look at National Weather Service forecasts, as the meteorologists there are “honed in on looking at their area of the country and can pick up subtleties that we may miss,” Persoff said.

Yet he and his team also do their own forecasting — looking at models from other sources, including the College of DuPage in Glen Ellyn, Illinois, which has a website that “allows us to glean the current conditions, the radar, satellite, and factor in what the weather models say,” he said.

In the field, he also uses a high-quality radar app on his iPad called RadarScope, along with physical clues such as how surface winds, temperature, and humidity are affecting the storm.

“Once the storm is established, the combination of radar and visual clues are very much like anatomy and function in a human being,” Persoff said. “There’s structure and function, and for me, that resonates very deeply as a physician.”

As the storm gets stronger, Persoff usually ditches the radar and relies on sensing its physical characteristics. There are ways to tell if a storm is strengthening or weakening, such as how the clouds are moving or how firm they look.

“When a cloud looks like you can walk on it, those tend to be associated with stronger storms, as opposed to puffy cumulus clouds that look like cotton balls,” he said.

Often, with supercell or “tornadic” thunderstorms, there’s rotation in the storm itself. “It can look like the storm itself is a spinning top, where everything is rotating around over the diameter of tens of miles at a decent velocity,” he said.

Another classic feature of a tornado-generating storm is a wall cloud, which looks like a portion of the cloud that’s lower than the rest of the cloud and spins much faster than the parent storm itself. It often appears right before funnels begin to drop out of the cloud, Persoff said.

Most tornadoes, he said, are short-lived, with an average lifespan of just under 7 minutes — though they can cause vast amounts of damage in that time.

‘Incredible Beasts’

While many people have described tornadoes as sounding like a “freight train,” Persoff hears something else: rushing water.

“There’s a continuous rumble that occurs with tornadoes from repeated thunder and the wind itself, which sounds not like a train to me, but more like a waterfall,” he said. “There’s a very low bass sound. You can actually feel the tornado from your feet up as well.”

One of his favorite days in storm chasing came in late May 2016 near Dodge City, Kansas, when he saw 13 tornadoes.

“That never happens,” he said. “Sometimes we’ve had three on the ground. Fortunately, they did almost no major damage, and it dissipated before it entered Dodge City.”

This past year, he was chasing storms in western Oklahoma, when a tornado touched down and lasted 20 minutes, again doing almost no damage.

“It was at sunset, and the sun came out behind it, and there was an incredible lightning storm as well,” he said, noting that the sky was orange and the lightning was purple. “You could hear the plunks as the hail popped off of our cars,” he added, noting the earthy smell of farmland in the air and birds singing.

“There is this epicness, this wonder, this fascination with seeing something so large and so magnificent,” he said. “[Tornadoes] really are incredible beasts.”

Hairy Situations

There’s plenty of awe, but there’s also anxiety in storm chasing. Persoff has been chasing for about three decades, and he still clearly recalls a transformative experience, in the days before cell phones and radar.

He had just witnessed an impressive tornado in Kansas, and continued to follow the storm, but ended up hitting an unexpected muddy patch on a dirt road and became stuck. The storm behind the one he was chasing was tornadic, too, but he wasn’t able to move as it rushed toward him.

He could only watch as a large tornado barreled his way.

“Fortunately it ended up not hitting me, but it passed very close to me, and there was nothing I could do,” he said. After that, he swore off chasing on dirt roads forever.

Years later, in 2011, he and his storm-chasing crew found themselves in Joplin, Missouri. While they didn’t see that infamous EF5 tornado, the accompanying thunderstorm was “remarkably intense,” he said.

They drove toward the town and encountered a police officer, whom Persoff asked where his medical expertise would be most helpful.

“He said, ‘Well St. John’s Hospital has been destroyed,'” Persoff said. “When he told me that a hospital had been destroyed, that was such a difficult thing for me to comprehend, because hospitals are built very solidly.”

Persoff went to the only other hospital in the area, Freeman Health System, and assisted in the emergency department, and then transferred to another facility in the system to help receive patients from St. John’s. He thinks he saw 50 to 70 patients that night, though it was hard to know for sure, he said.

Given those experiences, Persoff says he now hangs back: “I tend to be a distance away, where I know I can escape.”

While tornadoes generally behave in predictable ways, he said, the more powerful ones “can take on unexpected motion. They can jig when you thought they were going to jag. The closer you are, the more dangerous that becomes.”

For instance, some tornadoes can widen more quickly than they move. That’s what happened in Joplin. It started out a few tens of yards in diameter, but within 45 seconds it was three-quarters of a mile wide, he said.

“You can’t account for all of the variables the closer you are to the storm,” he said, adding that with the rise of social media, storm chasers today are pushing boundaries that can get them in trouble.

“The majority of storm chasers today have far too much trust in their radar and put themselves in positions of risk,” he said, “getting as close as they can to get the most extreme footage.”

Appreciating Nature on All Scales

The other 50 weeks of the year, Persoff finds quieter ways to engage with nature, including with macro snowflake photography, which just earned him a feature on Colorado Public Radio.

The dry Colorado air, particularly in November and December, helps shape “full blown stellar dendrites,” which are “classic snowflakes,” the ones with 6 points, Persoff said.

Zooming in on these tiny wonders reveals intricate designs, even at an average size of just 2 mm. They’re typically asymmetrical, since the forces that create the crystallization — humidity, temperature, and pressure — can be applied unevenly, Persoff said.

“It’s true that no two snowflakes are alike,” he said. “Even one snowflake won’t be alike on both sides.”

Photography has been his gateway to engaging with nature, as he received his first camera at age 8 and would try to create scenes that would tell a story. Dark, stormy skies always made for a better tale, Persoff said.

“For me, it’s about the wonderment of nature in all its sizes and kinds,” he said. “Weather is one of those areas. Snowflake photography is an opportunity to commune with nature as well. It’s much more peaceful and there’s much less harm likely to come.”