The video is heart-stopping — perhaps literally. The man nonchalantly walks his dogs, oblivious of the danger to come. Suddenly, the man topples — a brief flash of light and what looks to be a bright burst of illumination emanates from his heel. It’s gone in a flash. No bolt is ever visible, nor was there any flickering ahead of or behind the main bolt.

Alex Coreas was walking his dogs Thursday evening in Spring, Tex., a suburb 15 miles north of Houston. The wild episode was caught on camera at Stuebner Airline Veterinary Hospital. ABC 13 Houston reports that Coreas is recovering, and was revived by an employee of the veterinary hospital and several good Samaritans.

A GoFundMe created by Daena Coreas-Delgado, the victim’s sister, stated that Coreas was “in the Intensive Care Unit … starting to eat, engage, and have full conversations” as of Monday morning. At the time of writing, nearly $24,000 had been raised for his medical bills.

Coreas also suffered burns and lost hearing in his left ear.

However, he escaped with his life. That’s remarkable, because it looks as if Coreas suffered a direct strike.

With some meteorological sleuthing, we can try to piece together what happened in this incredible video.

Signs point to a direct strike

What is most noteworthy in the surveillance video is the fact that the three dogs were able to run away, seemingly unharmed, while the man was knocked unconscious.

That key factor increases the likelihood this was a direct strike to the victim.

Humans usually don’t die when the nearby ground is struck, partially because of their comparatively small leg span — and the fact that the charge entering one leg and exiting the other would not pass through the heart.

Creatures such as horses, dogs and other four-legged animals with a greater leg span are more susceptible to being killed by a strike to the ground nearby. The magnitude of the electric jolt a person or animal would feel is proportional to the separation distance between their legs, assuming the current enters one and exits the other. In addition, if the charge was to enter through a four-legged animal’s front or rear leg/paw, it would likely pass near — or through — vital internal organs before exiting the other set. That would increase the chance of death.

“It is a bit surprising that all of the dogs were able to run away,” said John Jensenius, a lightning expert with the National Weather Service.

The man reportedly required CPR and revival, another indication he was directly struck. Impacts this severe can occur with any sort of major electric shock; however, they are more common with more direct lightning strikes.

A burst of light

More telltale, however, is the burst of light that seems to shoot out of his back heel in the moments immediately following the strike. This could be the result of one of two things, or the combination of both.

It could be that, given he was walking and mid-stride at the time of the strike, his foot was ever so slightly off the ground. Overwhelmed with charge, his body would have had to provide a desirable path to the ground. If one wasn’t available, the charge, over a short distance, could create one.

The lightning may have found a better location to ground itself just behind the man, for which reason it could have arced out of his back foot or leg instead of the front.

Jensenius raises another possibility. “What appears to look like a spark near the victim’s feet is likely dust from a small impact crater in the sidewalk caused by the heat of the lightning and the rapid expansion of a small area of concrete,” he writes. A divot was discovered in the concrete following the strike.

That also suggests that the narrow — but extreme — bolt of electricity struck the man directly and exited through his body. A blasting of concrete would have occurred only where the main channel of 55,000-degree electricity entered the ground. Most bolts of lightning are only about an inch wide.

How could the man have possibly survived a direct strike? We can theorize a couple of possible solutions.

Why sweat and rain may have saved Coreas’s life

Odds are he was decently wet with rain. Depending on how insulating his rain jacket was, he may have also been sweating, since the weather was warm and humid.

The presence of a sweaty or rainy film of moisture coating him may have allowed much of the charge (not all of it) to flow around his body — rather than altogether directly through it. This is known as a flashover effect.

How powerful was the bolt?

Moreover, the lightning bolt may have had a rather small current when compared with many other strikes. The fact that we never see the bolt or flash is important.

“The actual lightning strike occurred very quickly and apparently between frames in the video recording,” said Jensenius.

Positive lightning bolts seldom flicker much and leap 10 times faster than negative lightning. So it’s plausible this was a weak positive bolt originating from the bottom of the storm (a more powerful bolt from the top of the storm would have more likely been fatal). Or, the man may have been struck by a negative bolt.

Coreas is “lucky to be alive”

Whatever the case, one thing is certain. “The victim is very lucky to be alive,” Jensenius wrote.

“[He’s] also very lucky that there were people nearby both willing and able to administer CPR to the victim until professional medical help arrived. That CPR was likely critical in reviving the victim and limiting any brain damage that could have occurred due to a lack of oxygen to the brain. It’s worth noting that those people who helped the victim were risking their lives as the dangerous conditions during the resuscitation efforts.”

Lightning strike victims do not remain charged following a strike, and CPR should be administered right away.

Nineteen people have been killed in the United States this year because of lightning strikes. Most recently, a 33-year-old man was killed on Sept. 28 in Independence, Kan. He had been approaching the finish line of a trail race.