LIGHTNING DEATH QUESTIONS REMAIN.

Byline: Charles F. Bostwick Daily News Staff Writer

Authorities said Monday they still don't know what a Palmdale man was doing when he was struck Sunday morning by lightning in his back yard.

A sheriff's sergeant speculated Robert Culbertson was watching the lightning storm. Relatives said he had been checking on his household animals.

A Los Angeles County fire inspector said he might have been using a garden hose to extinguish a burning tree struck by lightning and been hit by a second bolt.

A firefighter who was one of the first to reach Culbertson said he might have been inspecting a large branch broken off another tree by the storm.

``It's hard to say at this point what happened, what he was doing,'' said fire engineer Edwin Davenport, part of the first fire engine crew to reach him.

U.S. Forest Service officials said funeral services were pending for Culbertson, 47, who had worked for the Forest Service since 1975, most of that time in the Angeles National Forest in its Valyermo Ranger District.

Culbertson started off as a seasonal firefighter in the Valyermo district in 1975, after he finished three years in the U.S. Army. He was picked up on a permanent assignment in 1979 in the Cleveland National Forest, and after 14 months returned to the Valyermo area. He had worked as a fire engine captain and on fire prevention patrol, forest officials said.

Since April, he had been working as a dispatcher at the Angeles National Forest's Operations Coordination Center at Fox Air Field in Lancaster.

He is survived by his wife, Gail.

Firefighters said they went to the house Sunday to extinguish a burning tree, reported at 6:48 a.m. by a neighbor who heard the lightning strike.

But when they looked over the backyard fence, they saw Culbertson lying in the yard, about eight or 10 feet away from the smoking tree and not far from another tree with a large broken branch.

The firefighters kicked open the locked gate, went in and started to work on him. Culbertson's wife, awakened by the sound of the gate being kicked open, came outside as the firefighters were trying to save her husband.

After another bolt hit nearby, firefighters moved Culbertson into the garage to continue treatment. More bolts hit within 100 feet as they worked in there. Culbertson was pronounced dead at Antelope Valley Hospital.

Firefighters think lightning hit a large cottonwood tree, shattering it and blowing off a strip of bark most of the way down its trunk. Then the bolt jumped to Culbertson, striking him near the collarbone on his left side. The bolt blackened other spots around the yard as well.

``Looking at the tree, there was a path about 2-1/2 or 3 inches wide from where the lightning hit it all the way down the tree about to his neck height,'' Davenport said.