LANL scientists capture two record-breaking lighting megaflashes

LOS ALAMOS, N.M. — Lightning megaflashes are rare and they’re difficult to record, especially from the ground.

“You’d have to put your instrument in just the right place at just the right time to have a chance of even measuring a portion of the megaflash," Los Alamos National Lab scientist Michael Peterson said.

The advantage now is working from space using NOAA’s Geostationary Lightning Mapper.

Recently, scientists at Los Alamos National Lab recorded two new lightning flashes through the lab’s software that beat the previous records for lightning flash extent and lightning flash duration.

On April 29, 2020, this new world record lightning flash spanned nearly 500 miles, all the way from Texas to Mississippi.

The longest duration megaflash occurred in the La Plata basin – between Argentina and Uruguay – and lasted for just over 17 seconds.

"Normal lightning has a typical distribution of flash size and flash energy that we use as the basis for our guidance on lightning safety and engineering standards. The problem with megaflashes is that they break a lot of these rules,” Peterson said.

These megaflashes tend to occur from over the horizon from storms that you can’t even see from where you’re at. They also tend to produce multiple cloud-to-ground lightning strikes along their path.

The lightning strikes are also typically positively charged, which is more damaging and deadly than a common negatively-charged strike.

"So even though lightning megaflashes are very rare they are individually impactful as well and this is why we care about them,” he said.