Lightning ‘superbolts’ form over oceans from November to February

University of Washington

The dots represent superbolts, lightning with an energy of at least 1 million Joules. Red dots are particularly large superbolts, with an energy of more than 2 million Joules. Superbolts are most common in the northeast Atlantic and the Mediterranean Sea, with smaller concentrations in the Andes, off the coast of Japan, and near South Africa. Credit Holzworth et al./Journal of Geophysical Research: Atmospheres
The dots represent superbolts, lightning with an energy of at least 1 million Joules. Red dots are particularly large superbolts, with an energy of more than 2 million Joules. Superbolts are most common in the northeast Atlantic and the Mediterranean Sea, with smaller concentrations in the Andes, off the coast of Japan, and near South Africa. Credit Holzworth et al./Journal of Geophysical Research: Atmospheres

The lightning season in the Southeastern U.S. is almost finished for this year, but the peak season for the most powerful strokes of lightning won’t begin until November, according to a newly published global survey of these rare events.

A University of Washington study maps the location and timing of “superbolts” — bolts that release electrical energy of more than 1 million Joules, or a thousand times more energy than the average lightning bolt, in the very low frequency range in which lightning is most active. Results show that superbolts tend to hit the Earth in a fundamentally different pattern from regular lightning, for reasons that are not yet fully understood.

The study was published Sept. 9 in the Journal of Geophysical Research: Atmospheres, a journal of the American Geophysical Union.

“It’s very unexpected and unusual where and when the very big strokes occur,” said lead author Robert Holzworth, a UW professor of Earth and space sciences who has been tracking lightning for almost two decades.

Holzworth manages the World Wide Lightning Location Network, a UW-managed research consortium that operates about 100 lightning detection stations around the world, from Antarctica to northern Finland. By seeing precisely when lightning reaches three or more different stations, the network can compare the readings to determine a lightning bolt’s size and location.

The network has operated since the early 2000s. For the new study, the researchers looked at 2 billion lightning strokes recorded between 2010 and 2018. Some 8,000 events – one in 250,000 strokes, or less than a thousandth of a percent – were confirmed superbolts.

“Until the last couple of years, we didn’t have enough data to do this kind of study,” Holzworth said.

The authors compared their network’s data against lightning observations from the Maryland-based company Earth Networks and from the New Zealand MetService.

The new paper shows that superbolts are most common in the Mediterranean Sea, the northeast Atlantic and over the Andes, with lesser hotspots east of Japan, in the tropical oceans and off the tip of South Africa. Unlike regular lightning, the superbolts tend to strike over water.

Explore a visualization of the data at!/vizhome/Superbolts/Dashboard1.

“Ninety percent of lightning strikes occur over land,” Holzworth said. “But superbolts happen mostly over the water going right up to the coast. In fact, in the northeast Atlantic Ocean you can see Spain and England’s coasts nicely outlined in the maps of superbolt distribution.”

“The average stroke energy over water is greater than the average stroke energy over land — we knew that,” Holzworth said. “But that’s for the typical energy levels. We were not expecting this dramatic difference.”

The time of year for superbolts also doesn’t follow the rules for typical lightning. Regular lightning hits in the summertime — the three major so-called “lightning chimneys” for regular bolts coincide with summer thunderstorms over the Americas, sub-Saharan Africa and Southeast Asia. But superbolts, which are more common in the Northern Hemisphere, strike both hemispheres between the months of November and February.

The reason for the pattern is still mysterious. Some years have many more superbolts than others: late 2013 was an all-time high, and late 2014 was the next highest, with other years having far fewer events.

“We think it could be related to sunspots or cosmic rays, but we’re leaving that as stimulation for future research,” Holzworth said. “For now, we are showing that this previously unknown pattern exists.”


Co-authors are research associate professor Michael McCarthy and senior research scientist Abram Jacobson at the UW; and James Brundell and Craig Rodger at the University of Otago in New Zealand. The research was funded by the UW.

From EurekAlert!

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Mark Broderick
September 10, 2019 2:10 am

Well, that was a shockingly informative bit of science ! If only we could harness all that super raw power….

Walter Sobchak
Reply to  Mark Broderick
September 10, 2019 6:17 am

One super bolt is at least one million Joules of energy, one megajoule. One kilowatt hour of electricity is 3.6 mega joules. The study found 8,000 superbolts over a 9 year period. My house uses about 18,000 KWh per year. So 9 years of superbolts wouldn’t power my house for one year.

Robert W Turner
Reply to  Walter Sobchak
September 10, 2019 7:15 am

I stopped reading after the start of the second paragraph. Superbolts of 1 MJ is 1,000 times more powerful than the average lightning bolt? The average lighting bolt is only 1 kJ? 0.23 food calories? W.T.F?
A quick search shows that the average bolt is about 1 GJ of energy, which sounds more realistic. Is there some sort of imperial joule that I’m not aware of?

Reply to  Robert W Turner
September 10, 2019 8:05 am

According to , the average lightning strike is about 1 billion joules.

Walter Sobchak
Reply to  littlepeaks
September 10, 2019 11:02 am

maybe the chart is wrong. and a superbolt is 10^6 GJ or 1 PJ (Peta Joule). The convention is that 4.2 PJ = 1 ton of TNT. So a super bolt would be like a 500 lbs bomb.

Reply to  Robert W Turner
September 10, 2019 12:45 pm

Don’t know the magnitude of power but it’s a lot. Some years ago a large oak tree, about 3′ diameter, stood in the middle of a pasture across the road from our house. One morning, about 5 AM, a boom shook the house and woke us all up. The only thing left of that oak was a snag sticking up and circular pile of oak debris around it.
An oak tree that size would contain many gallons of water, converted to steam in a fraction of a second. That’s some energy! I sure wish I’d been able to see that happen.

Robert W Turner
Reply to  Walter Sobchak
September 10, 2019 7:18 am

Pretty sure they meant MEGA JOULES, a superbolt is 1,000,000 MJ.

Crispin in Waterloo
Reply to  Robert W Turner
September 10, 2019 8:37 am

A typical lightning return strike passes about 30,000 amps along the plasma “wire”. The voltage is in the 300KV range so I can understand were the MJ comes from.

At 300 KV, a 0.00001 second strike (consisting of 5-30 repeats separated by 50 ms) would pass 1-2 MJ. Perhaps they mean 1 or 2 thousand MJ per strike for the Big Ones.

300,000 x 30,000 x 0.00001 x say 20 pulses = 1.8 MJ

Then the Biggies are 1-2 GJ, right?

Eric H
Reply to  Crispin in Waterloo
September 10, 2019 9:25 am

Per the abstract (see link in my other post)
“One to one stroke comparisons with the Earth Networks Total Lightning Network show that all superbolts have peak currents over 10^5 Amps “

Steve Taylor
Reply to  Walter Sobchak
September 10, 2019 9:11 am

This isn’t about total energy per strike, just “radiated radio frequency electromagnetic energy per stroke” in the “in the VLF band between 5 and 18 kHz ” which is what they were measuring.

Eric H
Reply to  Mark Broderick
September 10, 2019 9:18 am

Conflicting reports on what the “mean” energy is in a bolt of lightning. MIT claims the average bolt is 1 million Joules (1MJ).
However, the U of W research abstract here:
claims it is 1000 Joules. However, they state they are only looking at a specific frequency range: ” The mean stroke energy is about 1000 Joules/stroke in the VLF band between 5 and 18 kHz …”

I am not an electrical engineer so I don’t know if they can both be right or…?

William Astley
Reply to  Eric H
September 10, 2019 1:20 pm

Eric, Per the paper you quote the total energy of a super bolt is 10 GW/strike, however the duration of the strike is small so the power Watt-hrs is small.

radiated radio frequency electromagnetic energy per stroke to identify the upper tip of the global lightning stroke energy distribution. The mean stroke energy is about 1000 Joules/stroke in the VLF band between 5 and 18 kHz while the distribution used in this paper is limited to strokes in that band above 1 MJ, about three orders of magnitude above the mean. It is shown that these energies are representative of the tip of the optical distribution, first identified by Turman (1977) above 10 GW/stroke which he termed ‘Superbolts’.

Reply to  Eric H
September 10, 2019 1:44 pm

Well, I’m an EE (who doesn’t know much about lightning). But 5-18 kHz is a relatively narrow band of radio spectrum. 1000 joules in that narrow bandwidth seems to me (without doing any calculations) to be compatible with a total energy near 1 MJ.

We know lightning bolts generate RF energy up beyond 10 MHz. 5-18 kHz is only about 1/10,000 of the frequency range between 0 and 10 MHz. I think the radio waves generated by lightning tend to be stronger at lower frequencies. So the energy in the range 5-18 kHz would be higher than the average energy/hz between 0 and 10 MHz.



Ian Magness
September 10, 2019 2:14 am

Superbolts in the northern hemisphere winter? Aren’t abnormal weather phenomena only due to global warming?
Seems the science is still settled then.

Reply to  Ian Magness
September 10, 2019 12:26 pm

“By seeing precisely when lightning reaches three or more different stations, …”

Uh, lightening doesn’t reach – i.e. strike – three different stations, or usually even one station. They all detect the stroke from some distance. Clarification needed.

Mark Broderick
September 10, 2019 2:18 am

More shockingly good science ! ….IMHO

“Scientists uncover new evidence of the asteroid that killed off the dinosaurs”

“The sediments also offer chemical evidence that the cataclysm blew hundreds of billions of tons of sulfur from pulverized ocean rock into the atmosphere, triggering a global winter in which temperatures world-wide dropped by as much as 30 degrees Fahrenheit for decades, the scientists said.{

Now that is Catastrophic Climate Change

Reply to  Mark Broderick
September 10, 2019 6:51 am

The area where the asteroid landed is rich in gypsum, which contains sulfur. There are those that speculate that had the asteroid hit just a few hundred miles in any direction, the dinosaurs might have been able to survive.

Jim Ross
September 10, 2019 2:21 am

Apart from (or in addition to) Peru and the more northerly parts of the North Atlantic, there would appear to be “clustering” along latitudes 40N, 0 and 40S.

Tom Abbott
Reply to  Jim Ross
September 10, 2019 8:11 am

There appear to be clusters in the middle of the United States, far from the oceans.

Jim Ross
Reply to  Tom Abbott
September 10, 2019 8:52 am

Indeed … at approx 40N. I don’t think anyone has suggested that they are completely restricted to the oceans. Certainly not me. Or the authors.

Bill Thomson
September 10, 2019 2:46 am

Very interesting. Perhaps only above sea water because it has more ability to conduct electric current.

Mike McMillan
Reply to  Bill Thomson
September 10, 2019 4:44 am

Probably because the sea is flat, no telephone poles, trees, or golfers to concentrate and raise the voltage.

September 10, 2019 2:55 am

We think it could be related to sunspots or cosmic rays….. Could all weather changes be due to sunspots, solar cycles and cosmic rays???

Bill Powers
Reply to  Sunny
September 10, 2019 3:10 am

Nah. Its our fault.

Reply to  Bill Powers
September 10, 2019 4:57 pm

No, Bill…it’s your fault! I’m not paying any silly carbon taxes!

Ronald Ginzler
Reply to  Sunny
September 10, 2019 7:57 pm

Wizards and witches had considerable influence in the MWP. Even earlier, Thor and Zeus had their influence. But since most of these superbolts are over oceans, perhaps the brotherly dispute of Poseidon and Zeus still exists.

michael hart
September 10, 2019 2:55 am

Something genuinely interesting and surprising.

September 10, 2019 3:25 am

No, your all wrong. Its CO2.

After all what else could it possibly be. Sark.


Reply to  Michael
September 10, 2019 4:51 am

It must be, we didn’t have the technology or ability until CO2 hit above 400 ppm!

Reply to  Michael
September 10, 2019 6:52 am

CO2 makes the atmosphere less conductive, so the voltage needed to form a lightning bolt has to be bigger.


Ron Long
September 10, 2019 3:51 am

Interesting. I wonder if “thundersnow” events are part of this spectrum? Does the reduction of these super bolts since 2014 mean the climate change crisis is abating? Never mind?

September 10, 2019 4:10 am

Perhaps its due cold unstable air over warm water like the Gulf Stream and the Mediterranean?

September 10, 2019 5:26 am

I assume they originate in thunderstorms. Thunderstorms off the coast of Norway/Norwegian Sea in the winter?

Keith Rowe
September 10, 2019 5:36 am

Perhaps mostly only happen over oceans because they need to build up enough energy differential to overcome and ground. With the land parts of Earth being up and down with a lot of different interface it allows a discharge when it reaches a much lower differential. Over oceans I would assume the charge would build and build over a large area of ocean until something happens or it just reaches a point where it happens because that is the maximum the system has before it grounds. My thoughts would think that there would be a maximum size of strike for the same area.

Reply to  Keith Rowe
September 10, 2019 6:25 am

Perhaps, but why wouldn’t summer ocean thunderstorms do the same thing?

James F. Evans
September 10, 2019 5:42 am

Looking at the above schematic, these “super bolts” seem to run in bands around the earth, as noted by a previous comment. This electromagnetic phenomenon would seem to be related to system wide processes rather than localized weather conditions (warm & cold fronts colliding).

System wide?

Yes, these observations & measurements suggest earth is an electromagnetic body.

But why is this expressed during a specific time of year (November to January)?

Tom Schaefer
September 10, 2019 5:49 am

I kept looking for the word “hail” in this article, and it is absent. How could you study something but ignore the generator of it? I think the fact these occur in winter is obvious: Relatively warm water, colder air. Thunder storms do form at cold fronts right? Also, “Super-bolts” may form simply because there are fewer ionized channels/anomalies paths (created by rising/falling air in proximity) over the relatively uniform sea/ocean, requiring the charge differential to build to a higher level before a bolt is released. I think you’ll find that super-bolts occur when the frequency of any sized bolts is reduced. I use to think about such things when doing neutral particle beam studies in the late 1980’s for ballistic missile defense.

James F. Evans
Reply to  Tom Schaefer
September 10, 2019 7:16 am

“[Hail]”… “the generator of it?”

Perhaps hail is not always associated with the phenomenon?

Also, the stations’ sensors may not have the capacity to detect hail.

But if it is only localized weather conditions that power these lightning bolts, why are they mostly limited to specific latitudes?

Yes, there are areas along these bands which are similar (oceans), but there are also areas along these bands which are dissimilar.

The continuity of the larger pattern suggests a larger system “generator” than localized weather conditions.

Dan Cody
September 10, 2019 6:39 am

This is going to come as a shock to some.

Reply to  Dan Cody
September 10, 2019 6:50 pm

It’s merely a current event and will soon pass.

Robert W Turner
September 10, 2019 7:31 am

I doubt they crack this nut anytime soon considering that there are still three unsolved problems for how lighting works in general.

September 10, 2019 9:12 am

Wondering how ancient mariners dealt with superbolts of lightning I happened across this …

(Keep in mind that these accounts were from the SURVIVORS of lighting strikes; it is anyone’s guess how many ancient ships were destroyed and sunk by superbolts, taking all hands down with them.)

A ship siphoning oil in the Gulf of Mexico was struck by lightning. What are the odds?

Joe Crawford
September 10, 2019 9:39 am

“The reason for the pattern is still mysterious.” Just looking at the distribution, the locations appear to somewhat match the Hadley Cell max vertical velocity descent areas on the map in the Wiki at:comment image.
Of course that Wiki map is for July and the the map of super bolts given above is multi-year. But, it might be worth investigating.

Joe Crawford
Reply to  Joe Crawford
September 10, 2019 9:40 am

Oops… forgot to end the italics :<)

September 10, 2019 9:40 am

This must be some of the “dangerous lightning” that our local weather forecasters are always warning us about. But I’m still trying to figure out which form of lightning is the non-dangerous kind.

Wayne Townsend
September 10, 2019 10:24 am

So, these superbolts happen (mostly in the N Hemisphere) when the N Hemisphere is tilted away from the sun, away from the solar wind. Makes one go, “Hmmm.”

Reply to  Wayne Townsend
September 10, 2019 12:25 pm

High-speed solar winds increase lightning strikes on Earth — ScienceDaily

Reply to  Marv
September 10, 2019 12:54 pm

Winter monsoons became stronger during geomagnetic reversal: Revealing the impact of cosmic rays on the Earth’s climate — ScienceDaily


When galactic cosmic rays increased during the Earth’s last geomagnetic reversal transition 780,000 years ago, the umbrella effect of low-cloud cover led to high atmospheric pressure in Siberia, causing the East Asian winter monsoon to become stronger. This is evidence that galactic cosmic rays influence changes in the Earth’s climate. The findings were made by a research team led by Professor Masayuki Hyodo (Research Center for Inland Seas, Kobe University) and published on June 28 in the online edition of Scientific Reports.


“The Intergovernmental Panel on Climate Change (IPCC) has discussed the impact of cloud cover on climate in their evaluations, but this phenomenon has never been considered in climate predictions due to the insufficient physical understanding of it,” comments Professor Hyodo. “This study provides an opportunity to rethink the impact of clouds on climate. When galactic cosmic rays increase, so do low clouds, and when cosmic rays decrease clouds do as well, so climate warming may be caused by an opposite-umbrella effect. The umbrella effect caused by galactic cosmic rays is important when thinking about current global warming as well as the warm period of the medieval era.”

September 10, 2019 10:33 am

Possibly related …

Watching lightning jets hit the ionosphere | Watts Up With That?


Gigantic jets are lightning-like discharges that spring from the top of thunderstorms, reaching all the way from the thunderhead to the ionosphere 50+ miles overhead. They’re enormous, powerful, and also fairly rare. The first one was discovered in 2001 by Dr. Victor Pasko in Puerto Rico. Since then only a few dozen have been recorded, almost always over open ocean.

Reply to  Marv
September 10, 2019 11:00 am

From one of the comments associated with this article …

“Effectively the discharges extend to space. And from there beyond to the magnetosphere, which then begs the question ‘Where is this electric current going to or coming from?’ and the answer is it’s coming from the solar circuit.”
“All planets have this connection to the solar circuit, which means that they are accepting electrical charge from the sun. It was imagined initially that these strange lightnings above storms were coming from the storm below. But the evidence is all in favor of the fact that the electrical energy is already sitting up there in the ionosphere waiting to get to earth. And it just comes down through those various elves, gnomes, the sprites – all of these whimsical names given to things that are not understood. Now once the charge gets to the thundercloud,
the electricity is distributed in the thundercloud, and then it is discharged to the ground through the normal lightning bolts. Or through tornadoes. Tornadoes are a slow electric vortex.”
~Wal Thornhill
interview with Peter Jupp

Reply to  Marv
September 10, 2019 5:04 pm

So… can I just string up a really long extension cord into space, float a geosync’d plug out there and get free electricity? /sarc

Reply to  leowaj
September 10, 2019 5:39 pm


Thomas Edwardson
Reply to  Marv
September 12, 2019 5:19 am

We are climate heretics. Wal Thornhill is a physics heretic. His explanation is simpler and more internally consistent than the religious orthodoxy. It goes something like this …

First, Sol sits at the center of a large electric field. We know this from measurements of the speed of the solar wind. The solar wind is comprised of charged particles which constantly accelerate away from Sol; faster at the orbit of Venus than at Mercury, faster at the orbit of Earth than at Venus. The only rational explanation for this acceleration of charged particles is the presence of an electric field.

Secondly, the Earth is a charged body. The fair-weather field of the Earth runs about 100 volts per meter of altitude, and totals more than a million volts by the time you reach the ionosphere. The Earth is connected to Sol’s electric field and solar wind at the ionosphere. Over time the charge separation between the earth and the upper atmosphere grows enough to exceed the breakdown voltage of the insulating air, and bang! Mega-lightning bolt. The Earth’s atmosphere can be thought of as a self-repairing leaky capacitor that experiences occasional short-circuit discharge via mega-lightning strikes.

During the Northern Hemisphere spring, summer, and fall, storms raise enough water vapor to more easily short out the atmospheric capacitor via smaller and more frequent normal-sized lightning strikes in thunderstorms, which reduce the frequency of the mega-lightning strikes by draining off accumulated charge. Venus lacks moisture, so the only lightning measured there is the mega-bolt variety.

So why the odd distribution of the mega-bolts on the map? Electric discharge in the atmosphere prefers to happen over the salty sea. Hanes Alfven noted the preference for the Northern Lights, an auroral discharge, to follow the coastline. The chances for mega-bolts increase in dryer air (lack of preventive thunderstorms), over saltier seas (good source of conducting ions), and where the distance between the earth and the ionosphere is thinnest (tops of mountains). The Mediterranean sea is the saltiest sea on earth, followed by the North Atlantic. The Andes are very tall, very dry, and close to the sea for a source of ions. And finally the 40N/40S latitudes do generally have drier air at the descending interface between the Hadley and Mid-latitude cells.

So why the increase in November and December? Earth’s orbit is elliptical, and perihelion occurs in December. Sol’s electric field is strongest at perihelion. So we are moving the charged body that is the Earth back and forth in an electric field which increases the electrical stress and alters the current flow in the atmosphere on a yearly cycle where the timing of the maximum current flow corresponds to a lull in the ability to loft water water into the atmosphere to short out the capacitor.

Jim Hughes
September 10, 2019 11:39 am

Looks like the super bolt clusters are located close to the lines of zero declination (agonic lines). There by possibly related to cosmic ray levels as well. Small magnetic world.

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