HOUSTON – I received this question early Monday morning:
“My name is Pete Campbell and I live in Kingwood Texas. I am retired, but I was an active SkyWarn spotter from 1971 until 2010. I worked out of the NWS office in Midland Texas with other ham radio spotters. Early this morning during the storms that passed through here I was awakened by the lightning. As I was awake and listening to the passing of the storm, I heard an extraordinary event that I had never encountered before. There was a lightning flash that lasted for approximately 15 seconds. The sky lit up as if it were daylight. The sound was loud but not sharp as with normal lightning. The sound was long and lasted the entire time but was unlike any sound I have ever experienced in all my years around thunderstorms, tornadoes, and a few very close lightning strikes while spotting. It was so extraordinary I got up and did some research on the internet and discovered the ‘megaflash’ events and in particular the 477-mile-long event that stretched from Texas to Mississippi. I now believe what I heard was one of these rare events. The local time was around 3 a.m., I would be interested to know if this was a megaflash event.”
One of our employees at KPRC 2 Senior Investigates Producer, Andrea Slaydon also noticed the strike. “I live in Kingwood,” she told me. “I also think I saw a flash that seemed to last a long time. I’m no expert, but I know it was longer than the regular flash.”
What is a Megaflash lightning strike?
Before we dive into Pete’s question, let’s start with a quick definition: A megaflash lightning strike is an unusually long lightning bolt that stretches at least 62 miles.
These aren’t your typical lightning strikes from an ordinary thunderstorm. Instead, they form within massive, highly electrified storm systems known as Mesoscale Convective Systems (MCS) which are large clusters of thunderstorms that behave as a single weather system.
Lightning itself comes in three main types: cloud-to-ground, intra-cloud (within the same cloud), and cloud-to-cloud. Megaflashes fall into the cloud-to-cloud category, where lightning travels horizontally across the sky rather than striking the ground.
We can track these impressive lightning strikes using our Live Stormtracker 2 Radar. The images below highlight the massive, electrified clouds responsible for these megaflashes. You’ll also notice that the conditions were just right for one of these lightning bolts to stretch over 62 miles!
The world record for a mega flash strike:
Within the storm cluster shown below, a single lightning bolt stretched an astonishing 477 miles! It started on the central Texas coast and went all the way to southern Mississippi on April 29, 2020. This record-breaking megaflash was captured with the help of researchers from Texas A&M University’s Department of Atmospheric Sciences.
The Houston Lightning Mapping Array network pinpointed where the lightning strike began, while the GOES-16 satellite measured its full length. The World Meteorological Organization later confirmed it as the longest lightning flash ever recorded, surpassing the previous record of 440.6 miles set in southern Brazil in 2018.
Was this a megaflash lightning strike?
Honestly, I don’t know for sure. Answering this would require a detailed analysis of lightning data by experts in the field. I did reach out to the Texas A&M Department of Atmospheric Sciences for insight, but I haven’t heard back yet.
That said, there are a few things to consider; the radar image below shows a gap in lightning strikes along the Texas-Louisiana state line. By definition, a megaflash forms within a Mesoscale Convective System (MCS), but in this case, the storms that moved through the southeastern U.S. on Monday morning were triggered by a cold front, and the line is broken rather than continuous. That means this wasn’t a classic MCS.
However, the system over southeast Texas was still strong enough to produce an exceptionally long lightning strike. Could there be other factors at play?
Two different kinds of lightning strikes:
There’s another possible explanation. Did you know there are actually two types of lightning strikes? Most people don’t.
About 95% of lightning strikes are negative, meaning they carry a negative charge from the cloud to the ground. But the rarer positive strikes come from the top of a storm cloud. These are sometimes called bolts from the blue because they can strike far from the main storm.
Since positive strikes originate higher in the atmosphere, they have to travel through much more air to reach the ground. That means they generate much stronger electric fields than negative strikes. And here’s the key: positive lightning flashes last longer and sound louder! That lines up with what Pete and Andrea experienced.
Oh, and one more mind-blowing fact, positive strikes can pack up to 300,000 amperes and one billion volts, making them far more powerful than typical negative strikes!
So was this a megaflash or a positive lightning strike? The answer isn’t clear just yet, but if I find out, I’ll be sure to update you!
Houston’s weather and other cool things explained by KPRC 2’s Chief Meteorologist Anthony Yanez.
