PHILADELPHIA -- In the past two months, an insidious intruder has repeatedly entered Tom and Patty Williams' home in rural East Bradford, Chester County, Pa., ruining two answering machines, their water heater control panel and their well pump.
Despite the expense (easily $1,000) and inconvenience (no hot water was tough, but no water at all was awful), Tom Williams tried to look at the bright side: Their annual $500 insurance deductible is out of the way, so the next loss should be completely covered.
"Of course," he said, "that means we probably won't get hit again until next year."
Lightning. Over the last four months, the megavolt vandal has been zapping the Philadelphia region like Zeus on a power trip, sending circuit-sizzling surges through power, cable and phone lines -- right into homes such as the Williamses'.
Fried in the process have been appliances ranging from big-ticket microwave ovens, televisions and computers to barely-worth-fixing toasters, coffee makers, electronic dusters and answering machines. Items with high-tech, computer-chip-enhanced features have been especially vulnerable.
For repair workers and for makers and installers of surge suppressors, the spate of violent thunderstorms has been good for business.
For utility and insurance companies still reeling from winter storm damage, it has been very, very bad.
"It is extraordinary," said Mike Wood, a Peco Energy Co. spokesman. "It has multiplier effects on costs for personnel and equipment."
"We're inundated with claims," said Bill Leone, a Pennsylvania district claims manager for Nationwide Insurance.
The Philadelphia area doesn't usually have a problem with lightning. Wind, rain and ice -- which can also wreak havoc with power lines -- are bigger concerns.
Florida is the nation's most lightning-prone state, because it has plenty of lightning's two major ingredients -- moist air and heat.
On average, a Philadelphia-area house is likely to get hit by lightning once in 60 years; a Florida abode will likely get hit every 20 years, said Martin Uman, an electrical engineering professor at the University of Florida at Gainesville who has made a career of studying lightning.
But this spring and summer have been anything but average in Phila- delphia. As meteorologist Mel Goldstein, who runs a storm detection center at Western Connecticut State University, explained, a tropical high-pressure system known as a Bermuda high has migrated north and dropped anchor off the mid-Atlantic states. With every cold front, the scene is set for fireworks.
Mr. Goldstein's storm center has counted 26 fierce thunderstorms in the Philadelphia area since April, compared to 10 during the same period last year. So Philadelphia homeowners were about as likely as Floridians to get hit by lightning this year.
Surge suppressors and lightning protection systems -- the updated version of lightning rods -- can mitigate the effects of lightning.
Peter W. Lewis, marketing manager for Intermatic Inc., a leading maker of surge suppression devices, said a good plug-in protector for a single appliance costs about $20, while a suppressor installed on a home's circuit-breaker panel runs about $100. Lightning protection systems are $800 and up, he said.
Still, if lightning hits close and hard, nothing can stop it. Experts estimate that the average lightning bolt packs 125 million volts, the equivalent of 2,875 million kilowatts of power. That's nearly six times more kilowatts than the entire electric generating capacity of the United States in 1970.
"The typical lightning arrester on a power line can handle 95,000 volts," Mr. Wood, the Peco spokesman, said.
Bruce Eisenstein, a professor of electrical engineering at Drexel University, refuses to worry about it. He hasn't even put surge suppressors on his computers.
"When I'm at home, I unplug. . . . Otherwise, I don't take any heroic measures," he said in a telephone interview during a recent rainstorm. "You're talking about a fairly improbable occurrence."
With that, his phone went dead.