How To Develop an Effective Lightning Detection System

Lightning strikes the Earth approximately 50 times per second with an average current of 30,000 amps and heat that exceeds the surface of the sun.  You would think that people would consistently be on guard against such a frequent and dangerous phenomenon. Yet, despite common safety guidelines, it often catches people unprepared. That’s why effective lightning detection systems are crucial for providing early warnings. Unfortunately, with so many different technologies to choose from, the process of developing a system can feel overwhelming.

This blog delves into why advanced lightning detection systems are essential and the different technologies that go into creating an effective system. In this post, you’ll discover:

• The dangers of lightning strikes, and why detection systems are critical.
• Which activities expose you to the greatest lightning risk.
• What goes into making a lightning detection system.
• How different lightning detection, visualization, and alerting technologies work (and which ones might work best for you).

Why early warnings for lightning are essential

Lightning is dangerous. Given the frequency and power of lightning, it’s no surprise that it causes a significant number of casualties. (The real surprise is that it doesn’t cause more). Around the globe, it’s been estimated that lightning causes about 24,000 deaths and 240,000 injuries each year.

In the U.S., those numbers are smaller but still significant. The average is closer to 25 lightning-related fatalities and about 400 lightning-related injuries per year. It is one of the leading weather-related causes of death in the U.S.

And surviving a lightning strike is just the beginning; up to 74% of survivors may be left with some form of permanent disability.

Unfortunately, our eyes and ears are not enough to keep us safe. Of course, someone might object to this claim by pointing to the 30-30 rule, which directs people to be in a safe place when there are 30 seconds or less between a lightning strike and the sound of thunder, then to wait 30 minutes after hearing the last thunder. Isn’t that a guideline to stay safe by using simple observation?

The reality is that the 30-30 rule is often misunderstood. Many people interpret it to mean that they should start moving to a safe place at the 30-second threshold, but the rule actually means you should already be in a safe place at that threshold. For fast-moving storms, even the first thunder may barely offer enough time to get to safety.

The fact is that the distances at which you can see lightning and hear thunder do not align with the distance at which lightning poses a threat.

• According to the National Weather Service, lightning can strike as far as 25 miles from the parent thunderstorm.
• If the flashes are sufficiently high, lightning can be seen hundreds of miles away, which is well beyond the range where it would make sense to take shelter.
• But thunder rarely travels through the air more than 15 miles. So, by the time you hear thunder, you are already within the danger zone.
• Incidentally, when you reach the 30-second threshold for the 30-30 rule, lightning is about 6 miles or closer, which is well within the 25-mile danger zone.

Who can benefit most from early warnings for lightning?

One way to approach the question of need is through the lens of risk. Those who are most at risk for suffering lightning casualties have the most to gain from early warnings.

The Lightning Safety Council recently published an important study of U.S. lightning fatalities from 2006 to 2023. Although lightning does not discriminate against people based on what they are doing, it is interesting to note that most lightning-related deaths (82%) were tied to outdoor work or leisure activities. The remaining deaths were from lightning strikes during daily routines or unknown activities. The 12 activities that contributed the most to lightning-related deaths were:

Once we know the activities that are most likely to lead to lightning-related casualties, we can get a clearer idea of which organizations or venues would most benefit from early warnings. Based on the top lightning fatalities: (1) beaches and (2) marinas would be obvious candidates for lightning detection systems. So would (3) farms, (4) ranches, (5) campgrounds, and (6) trailheads. Or, consider outdoor venues that accommodate gatherings, such as (7) parks, (8) country clubs, and (9) stadiums. Workers could benefit at (10) construction and outdoor renovation sites or at (11) any venue that requires large amounts of outdoor landscaping and yard work. Then there are outdoor public transportation hubs like (12) bus stations and (13) parking lots, whether they are standalone structures or parts of larger complexes like retail malls. 

Lastly, some venues or organizations may have stakeholders engaged in multiple higher-risk activities. Take schools as an example. They have students and teachers walking to and from school parking lots while others wait at bus stops. They have groundskeepers maintaining the school grounds. Many students play outdoor sports like golf. And, schools host numerous outdoor gatherings, such as sporting events, outdoor practices, and outdoor gym classes.

The making of an effective lightning detection system

Obviously, an effective lightning detection system needs to reliably detect lightning. But, that is only the beginning. The value of the information lies in what you do with it.

• One use is academic, studying lightning behavior to improve our understanding of this phenomenon.
• The other is practical, alerting stakeholders to nearby lightning in time to seek safety.

To serve these functions well, a lightning detection system will need to include software that centrally collects lightning data and helps users analyze and visualize the data in meaningful ways that expand situational awareness and enable decisive action.

The system should also be capable of alerting stakeholders to impending lightning threats in time to reach safety. There are a variety of communication channels that can be used to achieve that objective, and there are different approaches to triggering alerts. We’ll discuss these a little later.

Options for lightning detection

The centerpiece of any lightning identification system will be the network it uses to identify lightning; it’s critical to get this piece right. Depending on your location, you may want to build out your own network, or you may want to join an existing network. Either way, you’ll need to consider the technologies that comprise the network.

The main methods of detecting lightning can be divided into two broad classes: satellite-based and ground-based detection. And ground-based detectors can be further divided into audio, optical, and electromagnetic radiation sensors. Finally, electromagnetic sensors vary according to the wavelengths or frequencies they sense. In addition, some lightning identification systems are designed to predict the formation of lightning instead of observing it. We’ll touch on those briefly in a moment.

Satellite-based lightning detection

Satellite detection primarily uses light sensors on geostationary satellites to identify lightning in the atmosphere. The Geostationary Lightning Mapper (GLM), as it is called, went into operation for North America in 2017. Europe’s satellite detection system is called the Meteosat Third Generation Lightning Imager (MTG-LI). The GLM provides uniform coverage down to a resolution of about 10 km (6.5 miles). Its uniform coverage is its strength. However, its low resolution of 10 km means it may not be able to locate lightning precisely enough for some use cases. In addition, low-altitude lightning under heavy cloud cover may not always be visible to the satellite. And it cannot distinguish between in-cloud lighting and cloud-to-ground lightning.

Ground-based lightning detection

Although ground-based detection methods may not offer the same uniformity as satellite detection, many of them offer highly precise identification of the location, distance, and speed of lightning. And they are better positioned to pick up low-altitude lightning under dense clouds. However, there are still crucial differences between ground-based alternatives.

• Audio sensors: Audio sensors pick up on the sound made by thunder to provide information about the lightning associated with it. Researchers are just now coming to understand that audio signals may be able to provide information about lightning that we cannot readily detect through other means. However, that is still not fully understood and is still the subject of academic research. For practical uses, audio sensors share the same limitation as the 30-30 rule. By the time a storm is close enough to detect the sound of thunder, it is already in (or quickly approaching) the danger zone.

• Optical sensors: Optical sensors enable lightning to be detected from further away, but they require a clear line of sight. This can be problematic in mountainous areas and other areas with obstructed views. What's more, unless the optical sensor includes a 360-degree field of vision, it can easily miss lightning because it is pointed in the wrong direction.
• Electromagnetic radiation sensors: Lightning gives off electromagnetic radiation. Sensors can pick up sudden changes in radiation levels to identify the presence of lightning. But different sensors focus on different frequencies or wavelengths, and this makes a crucial difference in how they function.

• • Extremely low frequency (ELF) detection: The lowest frequencies of radiation travel farther. So, ground-based sensors tuned to lower frequencies can detect lightning from farther away. The advantage of an extremely low frequency network is that it can cover a large area with relatively few sensors. The downside is that this is the same frequency given off by power lines, making these sensors prone to interference. That interference can cause false-positive readings. Or, it can cause observers to miss signals from real lightning, as they may be drowned out by background noise. As a result, ELF sensors have extremely strict siting requirements and must be placed far from potential sources of electrical interference, which can restrict them from being placed where they are most needed. What’s more, in-cloud lightning tends to give off higher-frequency radiation that ELF sensors are less likely to catch.

• • Low to mid-range frequency (LF-MF) detection: Higher frequencies of radiation do not travel as far, so sensors that are tuned to higher frequencies cannot detect lightning as far away. But their range can still be considerable. For example, the electromagnetic sensors in our Earth Networks Total Lightning Network® (ENTLN) focus on the low to mid frequencies. Despite their focus on higher radiation frequencies, they are designed for a range of up to about 500-600 km, and they can still provide reliable detection as far away as 1,500 km. Networks of higher frequency sensors require greater sensor density than their lower frequency counterparts, but they are also less prone to electrical interference and offer more flexibility to be sited where they are most needed. What’s more, they are more likely than their ELF counterparts to pick up on in-cloud lightning.

Our preferred approach to lightning detection

Our ENTLN relies on our ground-based network of proprietary electromagnetic sensors. Ours is a Total Lightning System, designed to reliably identify and distinguish between cloud-to-ground-lightning and in-cloud lightning. What's more, our proprietary sensors provide 20x the frequency range of standard sensors, which significantly increases their detection capabilities, while avoiding the ELF frequencies that are susceptible to electrical interference.

But, as the saying goes, the proof is in the pudding. The accuracy and reliability of our lightning detection network speaks for itself. With its regional detection efficiency of up to 95%, independent studies have shown that our network tops the competition. And, the network’s location accuracy is now less than 100 meters (which means it offers significantly higher resolution than satellites alone).

A note on detection vs. prediction

Although our focus has been on different approaches to lightning detection, it’s worth noting that some solutions offer lightning prediction instead of detection. Predictive solutions claim to sense the probability of lightning via a sensor on the customer’s site. Unfortunately, predictive solutions do not even come close to the accuracy of observationally based detection systems.

We tested one such predictive solution against observations from the ENTLN over a seven-month period covering peak lightning season. During that period, 49 storms with lightning were tracked. On every metric, the predictive solution fell short.

• The predictive system missed 49% of the storms.
• It issued false alarms about 16% of the time.
• The predictive system gave an all-clear signal 14% of the time when lightning was still present in the area.

From lightning detection to situational awareness

Obviously, the point of collecting data on lightning strikes is to make use of it. And that begins with visualizing and analyzing the data to build up your situational awareness. That’s where software comes into the picture. The software you select should provide visibility into all the following:

1. Current lightning strikes: At the very least, you should be able to see precisely where lightning is striking in real time.
2. Comprehensive information about other weather-related hazards: However, as with most natural hazards, lightning rarely occurs in isolation. In fact, increases in lightning activity often precede other natural hazards, such as hail, tornadoes, high winds, and hurricane intensification. Lightning even causes about 10% of the world’s forest fires. That’s why we believe a multi-hazard approach to risk management is the right way to go. Instead of viewing lightning strikes in isolation, you should be able see them in conjunction with a variety of other severe weather data, including radar, precipitation, and wind, to name a few.
3. Current and forecasted information: While knowledge of the present situation is critical for guiding your response to immediate weather threats, the most effective responses often depend on extended preparation that begins ahead of time. For example, if you thought you might need to quickly evacuate a large number of people from a facility, you might want to instruct personnel to begin opening a number of secondary exits ahead of time. To give yourself the time you need to achieve that level of preparedness, you would need access to reliable forecasts, not just current weather data.

From awareness to action

Once you’ve identified the right lightning detection network and determined how you’ll collect and visualize the data, you’ll need to translate that information into action. That means figuring out how you’ll alert the right stakeholders in time to ensure everyone gets out of harm’s way.

Channels for communicating lightning threats

These are the three most commonly used channels for communicating lightning threats. The provider of your lightning safety system should be prepared to deploy any or all of these channels, depending on the needs surrounding your use case.

• Sirens and strobe lights: The advantage of sirens and strobe lights is that they can be seen or heard from a long distance. Even in scenarios where stakeholders may not have a direct line of sight to the strobe (like on a golf course), they can still hear the siren. And in scenarios involving loud noises that compete with the siren for attention (like an airport tarmac), the strobes remain visible.
• Public signage: This could be digital signage or television monitors that display warnings when lightning is detected within a predetermined area. While less ideal, it could even be a static sign that gets displayed when lightning is detected. While a public sign may not reach as far as a siren and strobe, it can convey more information to stakeholders. It’s a great option for supplementing warnings at key locations.
• Mobile alerting: Sirens, strobes, and public signs all share an important limitation. They provide the same information at the same time to all stakeholders within a fixed radius. If you need to reach stakeholders beyond that radius, or if you need to provide different stakeholders with different information at separate times, then you should consider supplementing your communications with mobile alerts. This should include email, text messages, and mobile app alerts.

Automated vs. manual alerting

Once you’ve figured out the channels through which you’ll alert stakeholders of lightning risk, you’ll need to figure out how to trigger those alerts. Historically, this was done manually; someone would be assigned to send out the alerts according to the organization’s protocols.

But manual alerting is fraught with problems. The most obvious is the potential for human error. But the bigger, more frequent problem is that manual processes can lead to costly delays in alerting.

Consider that most organizations want to minimize weather-related downtime. So, by the time an alert gets issued, the need for action is imminent. Even a short delay in sending the alert can endanger lives and property.

Now consider that the personnel assigned to send lightning alerts typically have many other job duties. When they attend to those other duties, their attention could be diverted for 10 minutes, 30 minutes, or more. That 10- to 30-minute delay  could make the difference between giving stakeholders sufficient time to seek safety…or not.

Automated alerting eliminates these problems. You may need to spend a little more time upfront to clearly define your lightning policies and alerting protocols. But that extra time can pay dividends by saving lives and property on the backend.

Bringing it together: Your next steps for lightning safety

Lightning systems provide critical early warnings that can prevent injuries and fatalities by giving people the time they need to seek safety. If you’re responsible for safety in a high-risk environment or simply want to improve your lightning preparedness, consider investing in a reliable lightning detection system. Explore the available technologies and assess how they can best meet your needs. For tailored solutions and expert advice on implementing effective lightning detection systems, contact us today and take the first step towards enhanced safety.