I’m going to get a little meteorologic here for a minute, but I’ll keep it simple as that’s about the extent of my expertise on the subject. The height of summer brings thunderstorms, which build when warm, moist air is subjected to convective activity or rising air currents.
As the water vapor rises, it condenses into cumulonimbus clouds that can build and tower well into the troposphere, reaching altitudes of 30,000-60,000 feet and higher in extreme cases. That’s high enough to affect airline travel. These puffy-looking clouds, like cotton balls, indicate weather so damaging even aircraft give them a wide berth.
Usually observed during afternoon hours, thunderstorms benefit from the sun heating the Earth throughout the day, creating that convection, and when severe, this rising air can be quite robust, sometimes throwing precipitation out the top of the rising air column.
As the atmosphere cools with altitude, moisture can freeze releasing hail from the most severe storms and dropping it miles away from the actual storm itself. That’s when you experience sunshine and rain or hail at the same time.
Lightning is a little more complicated, involving positively charged particles and negatively charged particles but there really are only a couple of important things to remember: if you hear thunder, there is lightning out there, too, and lightning is harmful stuff.
That’s the end of my weather summation, and I bring it up as background regarding how it relates to vehicles.
There’s a popular saying, “When thunder roars, get indoors” or some variation on that theme. But what if the only indoors is your car — should you get in?
The answer is yes. Cars are actually quite effective at protecting you from lightning strikes.
A few interesting facts about lightning: The average lightning bolt can produce a short burst of one terawatt of power or a trillion watts, enough to light up 10 billion 100-watt light bulbs. A bolt of lightning produces 1 billion-10 billion joules of energy, while the average defibrillator — the device used to restart a human heart in cardiac arrest — puts out a couple hundred joules.
Watts are a measure of power and joules are a measure of energy. Needless to say, getting struck by lightning is bad! Unless you happen to be driving a vintage DeLorean with a colorful scientist passenger attempting to traverse time, then all bets are off. And, not to criticize, but if I were to go back in time, I would consider choosing a different car. No, I have no experience with time travel, but we do have experience with DeLoreans.
Meanwhile, back to lightning strikes. The popular belief is that those rubber tires will insulate the vehicle, but current evidence and experts suggest otherwise. Those few square inches of rubber contacting the ground is actually pretty insufficient to provide any kind of meaningful insulation — in fact, rubber can become more conductive than insulative, if the jolt is powerful enough. Not to mention that all tires have embedded steel belts, which are quite conductive, running radially around their circumference — that’s why they’re called steel-belted radial tires.
The protection comes from the car acting as a Faraday cage, named for British physicist Michael Faraday, who discovered that a metal cage conducts the electrical charge around the perimeter and safely to the ground, thereby protecting the occupants.
The destructive nature of most thunderstorms is due to their high winds, which can topple trees and damage property; heavy rain that can cause flooding and water damage; and the impact damage caused by hail.
As for aircraft, they are designed to allow electrical current to pass through the fuselage without causing damage. Although unprotected electronics and avionics are vulnerable to electrical spikes, occupants are safe.
Wires, known as static wicks, are installed on trailing edges of wings and tails to aid in energy dispersion as it passes around the outer, aluminum skin. Engineered composite materials are becoming more prominent in aircraft manufacturing. These contain a conductive fabric mesh that performs the same conductive function as the stressed aluminum hull of a conventionally produced airplane. The danger to aircraft in a thunderstorm comes from the tremendous turbulence produced by the roiling air which can over stress an airframe and potential engine damage caused by excessive precipitation.
The safety of a vehicle’s occupants in a lightning storm is of course top priority, but vehicles can sustain damage to electrical components during these events, and there have been reports of lightning strikes causing vehicle fires.
Although a well-maintained car shouldn’t pose that risk, I suppose the presence of fuel vapor or improper electrical component installation could allow a certain vulnerability to fire, regardless of lightning exposure. The proliferation of electrical modules, computer engine management and infotainment systems in modern vehicles increases the likelihood of an electrical spike affecting the car. Concern peaks if power door locks and windows are rendered inoperative following a lightning strike, trapping the occupants. While protected from the immediate danger of lightning, this secondary risk may be more concerning.
Fully EV, or electric, vehicles would seem to be the most sensitive to a lightning strike, but engineers go to great lengths to protect these vehicles under a variety of conditions. Perhaps a separate issue is the current length of time while charging that could open EVs up to a different risk factor while plugged in. In at least one case of a Tesla getting struck by lightning while charging, some of the systems were affected but the vehicle was still operational.
Thunderstorms are nothing to be taken lightly, and lightning strikes can be deadly. So, when thunder roars get indoors — but if you can’t, get in a car.
Eric and Michelle Meltzer own and operate Fryeburg Motors, a licensed, full-service automotive sales and service facility at 299 Main St. in Fryeburg, Maine. More than a business, cars are a passion, and they appreciate anything that drives, rides, floats or flies.