With no rain or even clouds to warn him of the danger, death came literally out of the blue Thursday to a self-employed landscaper. The killer was a powerful bolt of lightning that cracked through perfectly clear skies.

David Canales, 41, of West Miami-Dade, was on the job at a Pinecrest home when the bolt hit. It first seared a tree, then traveled and struck Canales, standing nearby.

Experts said Canales was killed by a weather phenomenon fittingly called a ''bolt from the blue'' or ''dry lightning'' because it falls from clear, blue skies. He was pronounced dead at South Miami Hospital.

Canales is the latest victim of one of Florida's least enviable honors: It's the country's lightning capital. Five of the 47 people killed by lightning across the country last year were in Florida.

Dan Dixon, a meteorologist with the National Weather Service in Miami, said that when Canales was hit, a typical afternoon storm was forming but nowhere near the area.

Weather data showed that lightning activity picked up north of Pinecrest shortly before 1 p.m., as a storm gathered momentum and swept through Coral Gables and then downtown.

''Most lightning will come from the base of a thunderstorm, inside that rain-shaft area,'' Dixon explained. ''But occasionally, what we call a bolt from the blue comes out of a thunderstorm still several miles away.''

The fair-weather bolts pack a bigger, deadlier punch and form differently.

Most lightning bolts carry a negative charge, but ''bolts from the blue'' have a positive charge, carry as much as 10 times the current, are hotter and last longer.

The bolts normally travel horizontally away from the storm and reach farther than typical lightning, then curve to the ground. This bolt struck the front yard of a home at 10500 SW 62nd Ave.

''My wife said the sky was blue, but the lightning bolt was the most horrible sound she had heard in her life,'' said Clemente Vazquez-Bello, owner of the home where Canales and two workers had come to do landscaping.

Startled by the violent sound, Margarita Vazquez-Bello ran to the backyard. The men were not there. Canales' workers were knocking on the front door, seeking help.

She dialed 911. Officers with the Village of Pinecrest and Miami-Dade Fire-Rescue arrived at the home. But Canales was in grave condition when transported, said rescue spokesman Lt. Elkin Sierra.

The Vazquez-Bellos rushed to South Miami Hospital, where Canales was pronounced dead. Canales' wife, also at the hospital, could not be reached for comment.

Vazquez-Bello said Canales was ''a wonderful human being'' and a dependable hard worker.

''We feel terrible about this,'' said Vazquez-Bello, a Miami attorney.

Dixon said protecting yourself from such unexpected lightning is difficult.

''They are very unpredictable and very dangerous. We urge people to stay indoors even if you hear thunder only faintly in the distance,'' Dixon said. ''If you're close enough to hear thunder, you're close enough to be struck by lightning.''

Earlier this month, a worker was hospitalized after being struck at a construction site in Miami. Nine people, including three children, were forced out of their Plantation home after a lightning strike caused a fire.

There has been at least one fatality in South Florida this year: A person on a roof in Miramar was killed by lightning May 19, Dixon said.

It's not the first time in South Florida ''bolts from the blue'' have proven deadly.

In August 1988, a Norwegian couple vacationing in South Florida were struck while standing on a Fort Lauderdale beach. Witnesses said the sky was cloudless.

Miami Herald staff writer Penny McCrea and researcher Monika Z. Leal contributed to this report.