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41

Does lightning strike from the sky down, or the ground up? The answer is both. Cloud-to-ground lightning comes from the sky down, but the part you see comes from the ground up. A typical cloud-to-ground flash lowers a path of negative electricity (that we cannot see) towards the ground in a series of spurts. Objects on the ground generally have ...


15

You were most likely seeing lightning (to be sure, a date/time and your location would be necessary). Lightning can be visible from quite a distance and storms can be incredibly active with lightning within the clouds and from cloud-to-cloud. Given a large distance and being inside a (relatively) loud airplane cabin it is no surprise that you couldn't hear ...


15

Your map of lighting tells you where thunderstorms occur. Your second map of watches tells you where a subset of thunderstorms exhibiting severe threats (high winds, large hail or tornadoes). The type of thunderstorms that frequent Florida are air-mass thunderstorms and generally will not warrant a severe thunderstorm watch. The storms in the midwest that ...


14

Lightning happens when the potential difference between the clouds and the grounds becomes too large. Once the voltage reaches a critical strength, the atmosphere can no longer act as an electrical insulator. First, a stepped leader is created at the base of the cloud which is a channel through which electrons in the cloud can travel to the ground. But while ...


12

In the video, the downward strike created an ionized path. The brightness was less as the current was less because it was travelling through un-ionized air. The upward strike took the ionized path. The upward strike's current (brightness) was much greater as the electrons flowed along the ionized path as it had the least resistance. The current equals the ...


11

Positive lightning is indeed very interesting. According to the National Weather Service, the reason why it has a higher amperage and voltage is due to the due to the amount of air it must get through to reach the ground. Otherwise, it would never reach the ground. Since it originates in the upper levels of a storm, the amount of air it must burn ...


9

I'm pretty sure that lightning can go either way. We did the calculation in physics class, a bit of a back of the envelope calculation to be sure, but we came out with an electric field of 300,000 V/m being the electric field needed for lightning to form. What that means is, an electric field is created between the clouds and the ground by a build up of ...


6

Rain in a climate such as Ireland is most often stratiform. That is, it is created when moist air is lifted by a front, or by divergence in the upper troposphere. Thunderstorms involve buoyant air, which rises on its own due to its being warmer than its surroundings. Typically solar radiation is involved in heating the surface such that the air near it warms ...


6

While I wouldn't rule out that you were witnessing distant lightning lighting up the clouds below, or at some distance anyhow, there is also the possibility of the flashes being upper-atmospheric lightning such as Sprites. The half hour duration of the phenomena seems quite a long duration if we assume a plane in flight would cover somewhere about 300 miles ...


6

It's pretty likely. Florida has the highest lightning strikes of anywhere in the US, as can by seen by this map from lightningsafety.com This is the area near Florida, with the highest levels. It's hard to see, but the highest density is actually just to the west of the Cape, but it's not too far of a stretch to say it's the lightning capital of the US.


6

Annually, about 51 people die from lightning strikes per year in the United States. Part of the reason is the low probability of being hit by lightning. Tornadoes, hail, and straight line winds sweep large areas, while one lightning bolt covers a rather small area, and may even be harmless if it doesn't make contact. Think of it this way: if you were struck ...


6

From my knowledge, lightning is formed when a static charge develops between ice particles in a cloud, and the charge is neutralized via an electric strike to the ground. In a volcanic cloud, there is a lot of ash and very high temperatures. The ash is a substitute for the ice particles. The temperature difference between the ground and air allow for easier ...


5

The discharges are due to the charged particles carried aloft by the plumes rising from or shot from a volcano. The plumes may be dominated by positive charge but usually it also contains regions of negative charge. These regions can discharge to one another or to ground. The current in a discharge can heat the air so intensely that the air expands faster ...


5

I found the paper you initially referred to here: http://onlinelibrary.wiley.com/doi/10.1029/JB073i006p01889/full based on the hyperlink by the xkcd webpage you referred http://www.agu.org/pubs/crossref/1968/JB073i006p01889.shtml The full reference for this paper is: Oetzel, G. N. (1968), Computation of the diameter of a lightning return stroke, J. ...


5

Is the ratio of IC to CG lightning relevant? Yes. Primarily, severe storms tend to have very few cloud-to-ground (CG) strikes. Thus, the ratio of IC:CG is likely going to be very high.1 2 However, some severe storms do produce a significant amount of positive CG strikes. They would still have a high IC:CG ratio, but they would distinguish themselves by ...


5

Absolutely: The Blitzortung project has near real-time data for most if not all of the world. I've also never taken the time to research how lightning detectors exactly work, but it's likely similar... and you can read about the Blitzortung instrument here. Windy.com also appears to now have lightning data over at least the largest part of the globe (...


4

Here is another one -Lightning hits across the world You can also look at the TRMM lightning sensor data for older periods - Lightning Sensor Here is another site that shows world wide lightning strikes - WWLN and for those searching for lightning strikes in the Americas here is the link - Americas Lightning Strikes


4

There are many types of devices used for measuring lightning. The first natural radio wave receiver was also the first lightning detector invented by Alexander Stepanovich Popov. In 1896 Popov presented a paper on a wireless lightning detector he had built that detected radio noise from lightning strikes. Popov's discovered that lightning produces radio ...


4

Yes, most storm chasers are risking their lives to take lightning photos. Your likelihood of being struck is obviously higher the closer you are to where lightning is originating from. However, lightning is highly unpredictable, and therefore, there is not much you can do to avoid all odds of being struck. One suggestion would be to take photos from inside ...


3

As far as I know; no. Lightning can either come from large amounts of friction in the atmosphere, or from a discharge of built up energy sourced from space (primarily solar radiation) captured by Earth's magnetosphere. The same energy that causes the Auroras. That said, clouds will probably be present regardless of the source of the energy.


3

The easiest thing to do to make your copper pole safe would be to ground it and disconnect the lights from your house wiring when they aren't in use (if they are plug-in lights and not solar). This article on how lightning rods work is a pretty good explanation of why you do want to ground a tall, conductive pole. Electricity will travel the path of least ...


3

Any build up of static electricity in the ground will seek to connect with opposite charge in a storm cloud, and will spark through the line of least resistance. Any high metal structure, whether it is copper or not, is a candidate for the line of least electrical resistance. You may be able to protect your copper support by a higher lightning conductor (...


3

In Norwegian we call it kornmo (grain ripener); it happens in the late summer at a distance of more than 20 km so there is no sound. The English translation is: "sheet lightning - heat lightning - summer lightning". I am not sure if this covers the meaning we have for it in Norwegian; it is said that Thor, the god of thunder, swung his hammer over the ...


2

Apparently it is possible for the ionosphere to influence the conditions in the lower atmosphere. The following are relatively recent results from a paper in 2009, and a summary and up-to-date state-of-the-art can be found in this paywalled, upcoming chapter in a book. As it turns out, at least in the arctic regions, the ionosphere can have quite an ...


1

The maximum voltage which can possibly occur depends on the materials involved and the distance. When the breakdown voltage of an insulator is exceeded, the electric potential difference is large enough to force the material into becoming a conductor. This means that for example when the voltage between two points on the surface of the earth, or two in the ...


1

Unlike storms and floods, lightning strikes a single point. So the area directly affected by lightning is small in comparison. Another thing to consider is that when you see lightning, that does not mean it touched down to the ground. However, keep in mind the fundamental way that lightning causes destruction, death, property damage, etc: wildfires. Most ...


1

For a comprehensive literature review of sources of lightning fatalities data you can check the paper "Striking Back: An Assessment of Lightning related Fatality and Injury Risk in Canada", it covers US and Canadian sources. But if you want to know which one is the largest and arguably the best. That would be NOAA's Storm Database. The data you can access ...


1

I've done some research studies about the flash rate in various storms. My paper is now in review, but here is some info from this paper: We have computed measurements for supercell and moderate thunderstorms, counting CG+ discharges. There are 24 times more discharges in supercells than in moderate thunderstorms. Supercells on average had better ...


1

Volcanic lightning was documented by one of the earliest American volcanologists, Frank A. Perret in the 1940s. However, there was not much, if any, study of the phenomena until recently. According to this article, the electric charge develops close to the ground where the plume gas thrust region at a few hundred meters above the crater rim, where the ...


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