NORTH COUNTY -- Freak thunderstorms that burst through the marine layer Wednesday surprised parts of North County with lightning, explosive thunder and hail -- and left a landscape worker fighting for his life.

The man apparently was struck by lightning about 2 p.m. as he stood next to a palm tree in the yard of a house on Camden Place in San Marcos, said San Marcos fire Battalion Chief Rick Vogt. When firefighters arrived, fellow workers were performing CPR on the injured man, and medics continued lifesaving techniques en route to Palomar Medical Center in Escondido.

Fire and law enforcement officials said they did not know the man's condition or identity Wednesday night. Hospital officials declined to comment about the man, citing medical privacy laws.

A 35-year-old Fontana woman also was killed Wednesday afternoon when she was struck by lightning while standing by a tree outside her home, authorities said.

In other areas, the weather kept firefighters busy chasing a spate of small lightning-sparked fires. Utility crews were overwhelmed by thousands of North County power outages, and motorists at times pulled over to seek cover from pounding hail.

The day started under cool and quiet gray skies, but the stormy weather rolled into North County with a boom just as many commuters were settling into work.

At the NorthComm fire communications center in Rancho Santa Fe, power died amid an enveloping thunder clap about 9:30 a.m., a dispatcher said.

When a backup generator brought power up less than a minute later, a frantic call came in from a nearby resident reporting a violent explosion. It was apparently the thunder.

National Weather Service meteorologist Stan Wasowski said a Pacific storm centered off the coast of Central California was drawing in moisture and creating pockets of unstable air high above Southern California.

"Even though we're way down southeast of the center, there are these little areas here that are destabilized," Wasowski said.

He said such storms in June are rare, though not unheard of.

"We get these every five or 10 or 20 years," Wasowski said.

Isolated thunderstorms will be possible though Saturday morning as the storm moves west over Central California, with the greatest chance of more wild weather on Friday and Saturday.

Throughout Wednesday morning, small brush fires sparked by lightning were reported throughout North County. More than 500 bolts had struck by afternoon, according to the weather service.

Most of the fires had burned out or been rained out by the time firefighters arrived, said California Department of Forestry and Fire Protection Capt. Nick Schuler. In Valley Center, where some of the fires were reported, rain fell heavily at times.

At about 12:30 p.m. in Fallbrook, a lightning-sparked brush fire charred about an acre near Willow Glen Road and Margarita Glen before firefighters got it under control, Schuler said. Nobody was hurt and no structures burned, though sheriff's officials said that three threatened homes in the area were evacuated during the fire.

Because of the numerous lightning strikes, CalFire used an airplane to patrol the rural terrain between Fallbrook and Palomar Mountain. The air crew spotted no fires, Schuler said.

In San Marcos, firefighters doused a tree at Marilyn Lane and Olive Street set aflame by lightning, a dispatcher said. Heavy rain fell briefly about 2 p.m. along Highway 78 in San Marcos.

About 2,500 North County customers were without power for a while, according to the San Diego Gas & Electric Co. Web site. The outages were reported in Encinitas, Rancho Santa Fe, Fallbrook, Valley Center, Bonsall, Pala, Pauma Valley and Harmony Grove.

The outages began around 9:30 a.m. and new ones were reported throughout the day as the lightning continued to strike.

SDG&E spokeswoman Alison Zaragoza said crews were unusually busy, and estimated restoration times were pushed back throughout the day.

Just when it seemed the weather couldn't get any weirder, hail began to pummel parts of the region.

Marbled-sized hail pounded Del Mar on Wednesday afternoon, causing some dent-averse motorists to seek cover underneath gas station awnings. The spurt lasted about 10 minutes.

"It was gnarly, man," said Domenic Callero, a 31-year-old courier filling up at a gas station on Del Mar Heights Road. "I've lived in San Diego for 10 years and I've never seen anything like that."

Call staff writer Sarah Gordon at 760-740-3517.

Staff writer Craig TenBroeck contributed to this report.