A quick bolt of lightning can trigger blazes lasting months

Less than half a second.

That's how long it took to ignite this summer's stubborn fire in the Great Dismal Swamp - the time required for a bolt of lightning to snake between sky and earth, triggering a blaze that charred more than 6,000 acres and fouled the air for weeks.

Unpredictable and unstoppable, lightning is the spark that starts most wildfires, including those in the swamp. The latest broke out after an especially violent thunderstorm fired 3,000 bolts an hour at Hampton Roads.

Few things in nature are as humbling.

"We get a few storms with really big numbers every year around here," said Mike Rusnak, a meteorologist with the National Weather Service in Wakefield.

The impressive bolts don't come from storms like Hurricane Irene. They're too saturated inside to work up the kind of friction that generates such electricity. The real fireworks come from drier turbulence inside the towering dark clouds of summer squalls.

Context is hard to come by, though. Strikes that reach the ground - about one out of every four or five - are detected by a nationwide network of sensors, but archived records are rare, making it hard to compare storms.

Instead, the information is packaged by a handful of companies that sell real-time or after-the-fact results to weather broadcasters, airports, golf courses, utilities, insurance companies and other users.

Geographical averages are available, however. A map shows South Hampton Roads receiving about four strikes per square kilometer per year, the most in Virginia. Florida tops the scale with 16. The West Coast gets fewer than one.

But one is all it takes when a single bolt can zap a billion watts of electricity into a matchbox of dry tinder.

At the Great Dismal Swamp National Wildlife Refuge, the staff examines lightning data after every thunderstorm, especially ones that throw a lot of sparks but don't dump much rain.

"We get maps that tell us how much lightning came over the refuge and where," said Chris Lowie, refuge manager. "That's our first indication."

If the strafing looks worrisome, spotters board a helicopter to scout for smoke. With 113,000 acres to monitor, it's more gut than science. Lowie doesn't recall whether anyone went up in late July, after a weekend of storms unleashed thousands of strikes.

He only knows that on Aug. 4, a pilot who happened to be flying over the swamp sent a fire alert.

"We were surprised," Lowie said. "We were like, 'Really? Where?' "

A lightning map from July 24 shows "maybe two strikes landing around that area," Lowie said. "We know that this kind of fire can just sit there quietly for a while."

There might come a day when man harnesses the power of lightning, an idea that has long intrigued scientists. Most people, though, will always run in the other direction. Lightning stirs a primordial fear that's well-justified. Twenty percent of those struck die on the spot.

Tim Nuckols of Nuckols Tree Care in Virginia Beach installs copper lightning rods in the crowns of cherished trees.

"And I make sure there's not a cloud in the sky when I'm doing it," he said.

Storms like the one that lit the Dismal Swamp fire bring him a rash of calls from property owners with struck trees. Some trees survive the shock, but varieties with high water content, like tulip poplars, "turn into toothpicks," Nuckols said.

He'll never forget the day he was working in one tree and lightning struck another nearby.

"It exploded," he said. "And I found religion."

Joanne Kimberlin, (757) 446-2338, joanne.kimberlin@pilotonline.com