When lightning strikes metal, the enormous current heats the contact point so rapidly that the metal can melt, partially vaporize, and even explode outward from the surface within microseconds. A typical lightning bolt delivers tens of thousands of amperes at temperatures exceeding 30,000 K in the channel itself, and the metal at the attachment point can reach well over 2,000 K almost instantly. The exact outcome depends on the type of metal, the duration of the current, and where the strike lands, but the damage is rarely just a scorch mark. Beneath the visible crater, the metal’s internal structure changes in ways that compromise its strength long after the storm passes.
What Happens at the Point of Contact
The moment a lightning channel reaches a metal surface, current floods into the material at one concentrated spot called the arc root. Because the current rises so fast, it does not spread evenly through the metal. Instead, it crowds into a thin outer layer, a phenomenon engineers call the skin-depth effect. That concentrated flow produces intense, uneven Joule heating across the surface. The result is an outwardly propagating wave of phase transitions: the metal at the very center melts and may vaporize, while material slightly farther out heats enough to deform but not liquefy.
Laboratory simulations that replicate lightning-like discharges on metal plates have shown this process directly. As current surges radially from the arc root, it drives what researchers describe as asynchronous electrical explosions, where different rings of the surface blow apart at slightly different times because of the uneven current density.
1High Voltage. Observation and verification of surface electrical explosion driven by radial‐distributed pulsed current in laboratory lightning strike testThe energy budget at the strike point involves several competing processes: Joule heating does the heaviest lifting, but radiative emission and the flow of hot electrons into the surface also contribute. At lower current levels, thermal conduction helps carry heat away from the contact zone, limiting damage. At higher currents, above roughly 500 amperes, the energy input overwhelms conduction and the other processes dominate, meaning the damage scales sharply with current amplitude.
2International Journal of Thermal Sciences. Modeling the lightning continuing current electric arc discharge and material thermal damage: Effects of combinations of amplitude and durationCraters, Pits, and Resolidified Bumps
The most visible signature of a lightning strike on metal is the damage crater. Molten metal gets blasted outward from the pit, then cools and resolidifies in raised bumps around the rim. Studies of lightning-like spark discharges on metal electrodes show a clear pattern: higher peak currents and faster current rise rates produce deeper pits with larger volumes of displaced material. The depth and volume of the crater are governed primarily by the rise rate of the current, while the lateral spread of the damaged area depends more on the peak current itself.
3Physica Scripta. Study of wavy damage morphology on metal surfaces under lightning-like channel spark dischargeIn real-world cases, these craters can be surprisingly small in diameter but still catastrophic. A failure analysis of pipelines struck by lightning found that leaks and subsequent fires were caused by tiny punctures where the pipe wall metal had fused through. Lightning hit the ground nearby, ionized the soil around the pipe, and arcs formed between the ground-strike point and the pipeline itself, punching small holes via localized Joule heating.
4Engineering Failure Analysis. Pipeline failures due to lightningDamage You Cannot See
The crater is only part of the story. Below and around the visible damage, lightning fundamentally reshapes the metal’s internal microstructure. An investigation of lightning ablation on steel pipelines found that the affected zone is layered like an onion. Nearest the surface sits a remelting zone, where the metal melted and rapidly resolidified into a new crystalline structure. Below that, several distinct heat-affected zones fan out with progressively less disruption until you reach the undamaged base material.
5Engineering Failure Analysis. Studies on ablation failure on pipeline related to lightning strikesThese layers are not just cosmetically different. Hardness testing shows that the remelted zone is substantially harder than the original metal, with hardness gradually decreasing through each heat-affected layer back down to baseline. That sounds like it might be a good thing, but harder metal is also more brittle. The mechanical properties of the affected area no longer match the surrounding material, creating a weak point where cracking can initiate under normal stresses the structure was designed to handle.
5Engineering Failure Analysis. Studies on ablation failure on pipeline related to lightning strikesWork on aluminum alloy 7075-T6, a material widely used in aerospace, tells a similar story with its own twists. Lightning simulation on this alloy showed a reduction in how much the metal could stretch before breaking, along with increased hardness beneath the damage. X-ray analysis revealed that the crystal lattice itself had been distorted, with higher dislocation density and micro-deformation throughout the affected zone.
6Chinese Journal of Aeronautics. Microstructural characterization and mechanical behavior analysis of 7075-T6 aluminum subjected to simulated lightning strikes In practical terms, a piece of aluminum that looked intact after a lightning strike might have lost a meaningful fraction of its flexibility, making it more prone to fatigue cracking during the repeated loading cycles an aircraft wing endures in flight.
What Lightning Does to Aircraft Skin
Commercial aircraft get struck by lightning roughly once every one to two thousand flight hours, which works out to about once a year for an active airliner. The airframe is designed to conduct the strike current safely over the exterior, but the energy still has to go somewhere. A classic case study of a Boeing-type fuselage hit by lightning documented damage in the form of melting or partial melting of widely separated rivets and the Alclad aluminum skin around them. The affected area at each rivet was confined to a radius of about 6.4 millimeters, but multiple rivets across a large patch of fuselage were hit.
7ASM Failure Analysis Case Histories: Air and Spacecraft. Analysis of Aircraft Damage from a Lightning StrikeThis pattern makes sense given how lightning travels along a metal airplane. The current enters at one point, flows across the skin, and exits somewhere else. At rivets and seams, tiny gaps create local arc points where energy concentrates. Each rivet becomes a miniature lightning-attachment site, experiencing its own localized melting. The damage at any single rivet is small, but the scattered pattern means a large section of skin needs inspection.
Fuel systems are the highest-stakes concern. The U.S. Federal Aviation Administration requires that the design and arrangement of aircraft fuel systems prevent ignition of fuel vapor from direct strikes, swept strokes that slide across the surface, lightning-induced electrical transients, and corona discharge at fuel vent outlets.
8Federal Register. Transport Airplane Fuel Tank and System Lightning Protection Meeting these requirements involves multiple layers of protection: flame arrestors at vent outlets, bonding straps that ensure continuous electrical paths so arcing cannot occur near fuel, and careful material selection for any fastener or panel near a tank.
Power Lines and Overhead Ground Wires
Transmission lines are among the most frequently lightning-struck metal structures, and overhead ground wires, the thin cables strung above the power conductors to intercept lightning, bear the brunt. When a direct strike lands on these wires, the damage falls into three general categories. Sometimes the wire melts clean through, with obvious evidence of fusion and no stretching. Sometimes it melts partially, losing so much cross-section that it can no longer bear its own weight and snaps in a ductile, stretched-out fashion. And sometimes the result is a sharp, smooth brittle fracture with little visible melting at all.
9Engineering Failure Analysis. A case study of ruptures in overhead ground wire under a large lightning over 400kAA real-world failure on a 220 kV transmission line in Brazil illustrated all three outcomes at once. Four of the five wires in the ground-wire bundle were completely severed by melting. The fifth wire did not melt through, but its load-bearing capacity dropped by about 60%, from roughly 1,300 kilograms to about 530 kilograms.
10Engineering Failure Analysis. Ruptures in overhead ground wire — Transmission line 220 kV That fifth wire held on temporarily, but it was operating far beyond its safe margin. This kind of partial damage is actually more dangerous than a clean break in some ways, because it can go undetected until the wire fails during the next storm or under ice loading.
Metal Jewelry and the Human Body
When lightning strikes a person, the current mostly flows over the body’s surface in what is called an external flashover. But any metal in its path becomes a preferential conductor, concentrating current and heat in a narrow line. The results can be gruesome. In one documented case, a silver necklace on a lightning-strike victim melted completely and fused throughout a full-thickness burn wound along the neck and chest, with silver welded into the tissue.
11Burns. An unusual case of lightning injury: a melted silver necklace causing a full thickness linear burnA forensic case study described a direct lightning strike that caused crater formations in the brass clasp of a wooden bead necklace, melted brass zipper teeth, blackened and fused cowrie shell ornaments, and vaporized a silver chain necklace. Fragments of the silver chain were found embedded in the victim’s clothing, and the vaporized silver produced deep burns on the back of the neck.
12PubMed. A unique case of direct lightning strike Different metals on the same person experienced different fates: the silver vaporized, the brass cratered, and the cowrie shell fused. This is a direct reflection of each material’s melting point, electrical conductivity, and thickness.
The practical takeaway is not that wearing metal attracts lightning. There is no credible evidence that a necklace, belt buckle, or watch increases your probability of being struck. Lightning selects its path based on geography, height, and conductivity of the ground, not the presence of a few grams of metal on a person. But if a strike does occur, any metal touching your skin will concentrate the thermal damage in that spot, turning a survivable flashover into a deep focal burn.
Magnetic Imprinting on Rock and Metal
Lightning does not just melt and deform metal. It also magnetizes it. The massive current pulse generates an intense, brief magnetic field that can permanently reorient the magnetic domains in ferromagnetic materials. This effect is well studied in geology, where lightning strikes on rock outcrops leave behind a distinctive magnetic signature called lightning-induced remanent magnetization.
In laboratory experiments replicating lightning pulses on rock samples from the Vredefort impact structure in South Africa, researchers found that the magnetic intensity of the samples jumped by roughly an order of magnitude after the pulse. The ratio of natural remanent magnetization to the background susceptibility, a measure of how strongly magnetized the sample is relative to how magnetizable it is, increased dramatically across all samples.
13Geophysical Journal International. Lightning-induced remanent magnetization—the Vredefort impact structure, South AfricaFor metal structures, this magnetization is usually more of a nuisance than a hazard. Compass readings near lightning-struck steel beams or pipes can be thrown off, and sensitive equipment that relies on magnetic calibration may need to be recalibrated after a nearby strike. In geological fieldwork, lightning-magnetized outcrops are a well-known source of spurious readings that have to be identified and excluded from paleomagnetic datasets.
Lightning-Induced Surges in Cables
A lightning strike does not have to hit a metal object directly to damage it. The electromagnetic pulse radiating from a nearby strike can induce damaging surge currents in any metal conductor within range, including communication cables, power lines, and electronics wiring inside buildings. This indirect coupling is one of the most common ways lightning damages metal infrastructure, and it affects far more objects than direct strikes alone.
Testing with simulated lightning pulses shows that the type of cable and its shielding matter enormously. Twisted-pair cables with a shielding layer provide the best protection, absorbing more of the coupled energy before it reaches connected devices.
14Electric Power Systems Research. Transient induced response on cables by lightning electromagnetic pulse with different experimental conditions For shielded cables specifically, grounding both ends of the shield offers the most effective protection, and adding more shielding layers continues to help. Research shows that increasing from a single shield to multiple shields improved shielding effectiveness from about 14.6 decibels to 20 decibels, and increasing metal pipe coverage from 60% to 100% reduced the energy coupled into the cable by up to 60%.
15Electric Power Systems Research. Assessment of electromagnetic shielding effectiveness in multi-layer and single-layer shielded cables against the lightning electromagnetic pulse considering different shielding strategiesThis is why surge protectors and proper grounding matter even if your building has never taken a direct hit. A strike a few hundred meters away can still push enough transient current into your wiring to fry circuit boards and damage appliances. The metal in the cables acts as an antenna, picking up the pulse and funneling it indoors.
When Lightning Makes New Minerals
Perhaps the most remarkable thing lightning does to metal is create entirely new materials. When a bolt hits soil or rock containing iron-bearing minerals, the extreme temperature and chemically reducing conditions can strip oxygen away from iron oxides and produce metallic iron and even exotic iron-phosphide minerals. The glassy tubes left behind, called fulgurites, sometimes contain microscopic spherules of native iron and a mineral called schreibersite, an iron-phosphorus compound otherwise found mainly in meteorites.
A fulgurite from Glen Ellyn, Illinois, was found to contain schreibersite spherules ranging from about 10 microns to several hundred microns in diameter, embedded in a matrix of amorphous silica glass. Temperatures in the fulgurite core exceeded 3,000 K, and the chemical conditions were extraordinarily reducing, roughly seven orders of magnitude below the iron-wüstite oxygen buffer. Under those conditions, carbon in the soil acted as a chemical sponge for oxygen, allowing metallic iron and silicon carbide to form.
16Nature Communications. Lightning strikes as a major facilitator of prebiotic phosphorus reduction on early EarthAn earlier study of a fulgurite from southeastern Michigan documented even more extreme products: centimeter-sized metallic globules rich in native silicon, a metal that normally exists only in combination with oxygen in the Earth’s crust. Thermodynamic calculations indicated temperatures above 2,000 K and reducing conditions approaching the point where silica breaks down into silicon metal and oxygen.
17PubMed. Lightning strike fusion: extreme reduction and metal-silicate liquid immiscibilityThe reason this matters beyond geological curiosity is that schreibersite is a plausible source of chemically reactive phosphorus, the kind that could have participated in the origin of life on Earth. Before lightning research brought this connection to light, the main proposed source of reactive phosphorus was meteorite impacts. The realization that ordinary lightning strikes on common soil minerals can produce the same compounds billions of times per year opens a second pathway for supplying a key ingredient for prebiotic chemistry. So when lightning strikes the metals locked inside ordinary dirt, it does not just melt them. It transforms them into something that may have helped kick-start biology on this planet.