Threat from above: Protecting against lightning strikes.

In 1997, Roy Scheider and his wife, Brenda Siemer, were sitting in their oceanfront house in Sagaponack watching a summer storm roll across the South Fork. It was one of the typically fast moving thunderstorms spawned by evening cold fronts pushing through hot, humid air at that time of year and it was a showcase of lightning. Bolt after bolt arced down from the sky with staccato cracks of thunder.

With the nearly unobstructed view afforded by their house, bounded by the ocean on one side and potato fields on the other, the couple had front row seats to one of nature’s most beautiful displays.

They were also about to learn a lesson about one of nature’s most dangerous forces.

“We could see the lighting bolts hitting the fields,” Ms. Siemer recalled recently. “It was beautiful and we sat and watched as it came toward us. Then we were hit.”

With an explosive crash that shook the couple’s house on its foundation, a bolt of lightning struck the brick chimney. The top of the chimney exploded from the strike, sending bricks flying hundreds of feet into neighbors’ yards and cascading down into the house. The wires of the phone and electrical systems along an entire side of the house sizzled and popped.

The couple was actually lucky. Some homes struck by lightning have seen large chimneys collapse entirely, sending thousands of pounds of bricks crashing through the roof and sometimes second and even first stories of the house.

Early last month, a lightning bolt struck the roof of a Water Mill house, igniting a fire that completely destroyed the structure before firemen could get it under control.

In large houses, miles of electrical wiring and thousands of dollars in electronic equipment can be destroyed—even vaporized—in an instant.

Conventional wisdom teaches us that lightning striking is one of the most unpredictable forces in nature—a one-in-a-million event so random and rare that it must be the instrument of luck (bad luck, that is) or an enraged deity. But for a house, all wires and wood, a lightning strike is hardly random, or particularly rare.

On the East End in particular, where the terrain is largely flat and lightning-producing storms are fairly common, lightning striking homes is a clear and present danger. Modern designs and increasingly complex internal electrical systems have made the large, modern houses common on the East End even more prone to strikes. Even the sandy composition of the soil on the East End makes property more vulnerable.

Most standard homeowners’ insurance policies cover damage from lightning strikes, says Kristen Squires of Maran Corporate Risk Associates in Southampton. The company deals with about half a dozen lightning-related insurance claims a year, she said during a recent interview.

Avoiding a lightning strike to your house is essentially impossible—short of an appeal to a higher power. There is no way to mask your house from the wandering charge of a developing bolt of lightning.

But protecting your home from the effects of lightning strike is possible.

In Europe, lightning protection systems are standard on almost every home. But American building codes rarely require any sort of specific protection. The odds of lightning strike are very low, but with the potential costs of a strike high, many insurance policies will offer discounts to homeowners who install protection systems.

A typical house is only moderately attractive to a lightning bolt. But large homes, with up to 20 miles of wiring connecting numerous video, audio and control systems and large HVAC units mounted in their attics, can be veritable bull’s-eyes for a lightning strike.

For the most part, the threat posed by lightning to a house is two-fold. The most terrifying, though most rare, is the danger of a fire being ignited within the house, either by the bolt itself striking the roof or another portion of the structure that is flammable—as was the case with the Water Mill fire—or by the super-heated charge of the bolt racing through the interior of the structure, jumping from wiring to pipe to plaster with fire-igniting sparks. More commonly, the effects of lightning strikes are seen in the electrical systems and electronic devices inside a house, which can be completely destroyed.

Little known, but true, lightning does not have to strike a house directly to do damage. A strike on the ground as much as a mile away can send an electrical charge—a power surge—into a home’s electrical system.

Homes with accessory buildings like garages or pool houses that have electrical systems connected to the main house, or those with extensive landscape lighting, can draw strikes that are directed into the home as though it had been struck itself.

Surge protectors on electrical outlets can protect appliances in most instances, but protecting hard-wiring requires more drastic measures. The key, should one decide not to rely on the odds, is being prepared for when a lightning bolt is searching for a place to attach itself, says Bill Skinner, co-owner of Long Island-based Applied Lightning Safety Group.

“When lightning hits a house ... It will find the path of least resistance,” Mr. Skinner said. “It cascades down through the house. It burns its way through electrical wires, if it passes a water pipe it can jump to that. The arcing, when it jumps, is where your fire hazard is.”

The main parts of a protection system are structural protection, essentially making sure the bolt of lightning doesn’t actually strike the house itself, and charge transfer, getting the electrical charge from the lightning bolt into mineral-rich ground, where it is neutralized, as quickly as possible. The primary component of structural protection is the lightning rod. Unlike lightning rods of old, which were tall and ornately decorative, today’s lightning rods rarely stick up more than 12 inches and are meant to be as unnoticeable as possible—small and thin and sometimes hidden in banisters or weather vanes.

Rather than just a single rod, a modern protection system may employ a half-dozen or more rods for a typical house. And large estates may require as many as 50 rods.

To transfer the extraordinary energy of a lightning bolt through a house safely, each rod is connected to a series of copper strand cables that snake throughout the house, as far from other conductive materials like wiring and metal pipes as possible. Copper is highly conductive and the cables offer the lightning bolt’s charge the easiest path to follow toward the ground.

Because sandy soil will often not absorb the charge on its own—sand is effectively ground up glass, which is not a conductor—Mr. Skinner said that structural protection systems on the East End must often be drilled deep into the ground to the groundwater table in order to be safely neutralized.

Comprehensive lightning protection isn’t cheap. For the large homes that Mr. Skinner and his partner John Murtha’s company works on, the systems can run from $20,000 to more than $50,000. But, when compared to the potential for damage to vastly more expensive electronics, that can be a small price to pay for wealthy homeowners.

On smaller homes, a protection system might run between $5,000 and $12,000, depending on the size of the house. Installation is cheaper if done during initial construction of a new home, Mr. Skinner said. It can also be more effective because the amount of electrical wiring used in a small home isn’t usually as vast and lengthy as the 20 or so miles needed to run a big house.

Applied Lightning Safety Group works on very large houses almost exclusively but several local electrical contractors offer lightning protection services and are listed in the phone book.

Ms. Siemer said that after the strike that blasted her chimney apart, she and her husband sought the advice of neighbor Bud Topping, a sage farmer who she said had the answer to everything. “Bud said there are two things you can do: you can put up a lightning rod or you can not put up a lightning rod ... Either way you’re going to get hit,” she said, offering some advice of her own, gleaned from experience. “We’re just mortals on this earth. We’re not going to stop Mother Nature. So why not invite her to travel down the inside of your chimney and into the ground.”