The rare and mysterious phenomenon known as a ‘superbolt’ boasts more than one million joules, enough to power the average US home for a month. Researchers who have been analysing the mysterious phenomena for almost 20 years are still unsure why or even how these ultra-powerful bolts strike, but they know the season is approaching. As the lightning season in the northern hemisphere draws to a close, the ‘superbolt’ season should begin in November and last until February, according to Robert Holzworth, a University of Washington (UW) professor of Earth and space sciences who has been tracking lightning for the best part of two decades.
Prof Holzworth manages the World Wide Lightning Location Network, a UW-managed research consortium that operates about 100 lightning detection stations around the world.
Data the team has gathered since 2000 showed just 8,000 of 2 billion lightning bolts were superbolts – equating to four millionths of a percent – which shows just how rare they are.
This meant they have been exceptionally difficult to study but now with almost 20 years’ worth of data, researchers have noticed a pattern.
The team discovered, according to the research published in the Journal of Geophysical Research: Atmospheres, the superbolts tend to happen between November and December.
What’s more is that they tend to strike over water, mainly the Mediterranean Sea, the northeast Atlantic and over the Andes.
Prof Holzworth said: “It’s very unexpected and unusual where and when the very big strikes occur.
“Until the last couple of years, we didn’t have enough data to do this kind of study.
“Ninety percent of lightning strikes occur over land. But superbolts happen mostly over the water going right up to the coast.
Lightning season is usually in the summertime, but superbolts do not follow this pattern, mainly happening in the northern hemisphere over the autumn and winter months.
Experts remain stumped as to why this happens, and what causes superbolts, but research will continue.
Prof Holzworth continued: “We think it could be related to sunspots or cosmic rays, but we’re leaving that as stimulation for future research.
“For now, we are showing that this previously unknown pattern exists.”