New sensors record 440-mile lightning megaflash

The World Meteorological Office has confirmed new records for the length and duration of lightning, doubling the previous records. The so-called megaflashes were identified with the help of new satellite observation systems.

The results were published in American Geophysical Union’s Geophysical Research Letters. The distance record was taken by a flash of more than 440 miles (709km) seen over in southern Brazil in 2019, greater than the distance between London and Glasgow. The duration record went to a 2019 flash over Argentina lasting more than 16 seconds.

Lightning was previously measured indirectly by ground arrays, which detect the bursts of radio static it produces. Scientists suspected this might not be catching the full extent of the largest strokes, and new sensors proved them right. Now they can observe lightning directly with a variety of satellite-based instruments, including dedicated Geostationary Lightning Mappers.

While most lightning flashes are less than 20 miles (32km) long and last a fraction of a second, rare megaflashes, between positive and negatively charged clouds, can be very much bigger.

Superbolts are another type of extraordinary lightning that hit the ground with unusual power. These can have 1,000 times the energy of a regular lightning strike, but unlike megaflashes are more often found in the northern hemisphere in winter.