That was some lightning storm in Austin during SXSW, huh?
A lot of music lovers had their South by Southwest plans interrupted last night when a storm moved through Austin, canceling shows and sending people running for cover. While the wind and rain didn’t end up causing much damage, the lightning that accompanied it got a lot of attention.
For more than an hour, the skies over Austin flashed and rumbled with seemingly constant electric activity. People took to social media, posting videos of what, for some, seemed like a once-in-a-lifetime light show.
“Unreal,” wrote one observer.
“Never seen anything like it,” wrote another.
“What causes this constant lightning?” asked a third.
“We were getting about three strikes per second, which is considered a lot,” Austin meteorologist Mary Wasson confirmed. “And most of them were cloud-to-cloud [lightning strikes].”
Cloud-to-cloud lightning is lightning that reaches from one cloud to another, never striking the ground. Cloud-to-ground lightning moves from the sky to the ground, posing greater danger and often causing louder noise.
The prevalence of cloud-to-cloud lightning in this storm is consistent with the low constant rumble of thunder noticed by some observers.
In total, the National Weather Service’s Nick Hampshire says Travis and Bastrop counties saw around 3,200 instances of cloud-to-cloud lightning and around 1,300 cloud-to-ground lightning strikes between 9 p.m. and 10 p.m.
“Things just looked pretty vibrant and pretty electric,” he said.
Hampshire says a 3-to-1 ratio of cloud-to-cloud lightning, versus cloud-to-ground lightning strikes is “pretty close to normal.”
Lightning occurs when ice inside of clouds generates electricity. When enough of it is produced that energy discharges to another point, either in another cloud or on the ground.
Meteorologist Wasson said by the time the storm system reached Austin, the conditions were right to create a lot of lightning, but little hail or rain.
“Just a lot of ice formation and crystallization up in the higher elevations and that causes friction, static electricity, and there you go!” she said.
But she said another ingredient made the storm even more memorable: All the people in town for the music festival to witness it.
"I was thinking, 'They’re getting a pretty good show!’” she said. “They don’t even need to listen to the music. They’re just seeing all the strobe lights in the sky!”