It marks the first firefighter death in the outbreak of wildfires in Southern California.
Department of Forestry spokeswoman Cathy Fritz said she had no additional details on the firefighter's death.
Matt Mathes, regional spokesman for the U.S. Forest Service, said the firefighters were injured in Julian, a historic mining town known for its apple crop. He said the two injured firefighters suffered critical injuries.
At least 17 people have now died since Oct. 21, and more than 1,600 homes have been destroyed. Glenn Wagner, San Diego County chief medical examiner, said he expects the death toll to rise as crews inspect hundreds of charred homes.
"I'm sure we're going to find folks who simply never had a chance to get out of their houses," Wagner said.
The fires, slowed little by ebbing winds, marched on Wednesday and threatened to all but obliterate some mountain towns.
The peaks of the San Bernardino range east of Los Angeles and the mountains of eastern San Diego County became major fronts Tuesday in the long arc of wildfires that have roared over more than 567,000 acres — about 890 square miles, nearly the area of Rhode Island.
The Cedar Fire in San Diego County had already destroyed 200 to 300 homes on the south side of Julian. Firefighters made preparations Wednesday to make a stand to save the rest of the town, said sheriff's spokesman Chris Saunders.
"They are vowing to save it," Sanders said.
With a 45-mile-long front, the Cedar Fire was just miles from merging with a 40,000-acre fire near Escondido, west of Julian. That fire had grown from 37,000 acres late Tuesday but was 20 percent contained, said Kathleen Schori, a spokeswoman for the Department of Forestry.
Fire crews exhausted by three days of battle in San Diego County were pulled back Tuesday.
"There's really no way to stop this fire from getting up to Julian," said Rich Hawkins, a U.S. Forest Service fire chief. Reinforcements were sent out, but Hawkins said he needed twice as many.
Ten miles south of Julian, about 90 percent of the homes had been destroyed in Cuyamaca, a lakeside town of about 160 residents, said Chief Bill Clayton of the state Department of Forestry.
"I'm sad to say the community of Cuyamaca was destroyed this afternoon," Clayton told reporters in San Diego.
In the San Bernardino Mountains, firefighters set backfires along a narrow highway, hoping to burn out fuel needed by the wildfire moving up from below. But the fire still jumped the road in some areas.
"We just pick a line in the sand and try to stop it. Sometimes we have success, sometimes we don't. We just keep trying," said William Bagnell, fire chief in Crestline, a small community high in the San Bernardinos.
Fire burning up the south face of the range threatened resort communities from Lake Arrowhead east to Big Bear Lake. Some 80,000 full-time residents had evacuated since the weekend, including thousands who jammed the highway out of Big Bear with bumper-to-bumper traffic Tuesday.
The 57,232-acre Grand Prix fire was 35 percent contained. The 26,000-acre Old fire was only five percent contained.
New mandatory evacuations were ordered during the night for residents of the Summit Valley area northwest of Lake Arrowhead, but residents of some communities on the other side of the mountains were allowed to return, said Candace Vialpando, a fire information officer.
Many of those who have died in the fires are believed to have ignored evacuation orders. Four people perished when flames forced firefighters to abandon a San Diego enclave without warning residents, the Los Angeles Times reports.
The fire danger was particularly high in the San Bernardino National Forest because millions of trees have been killed by drought and a devastating infestation of bark beetles.
Changing weather offered both problems and promise. Cooler, moist air was expected to replace the hot and dry Santa Ana winds, and lower temperatures were expected. But wind off the ocean could push fires east instead of south and west, said Brandt Maxwell, a meteorologist with the National Weather Service in San Diego.
It will take until Thursday or even Friday, Maxwell said, before the moist wind raises humidity in the bone-dry mountain areas where the fires were fiercest.
"We do have westerly winds that will continue to push the fire upwards into the communities of Lake Arrowhead and Big Bear," said Carol Beckley, fire information for the Old Fire in San Bernardino County. "It really could become catastrophic if the winds continue."
"Lower temps during the night helped somewhat but it doesn't look good," Beckley said.
More than 11,000 firefighters were on the lines of what Gov. Gray Davis said may be the costliest disaster California has ever faced. He estimated the cost at $2 billion.
"This is a total disaster," he said.
Gov.-elect Arnold Schwarzenegger, on his first visit to Washington since his Oct. 7 election, pleaded for additional federal resources.
At least 10 major fires were scattered along an arc stretching from northwest of Los Angeles south to the Mexican border. Some were believed set by arsonists; the Cedar Fire was ignited by a lost hunter's signal fire.
The San Bernardino sheriff has released a sketch of one of the two suspects believed to have started the fire, reports CBS News Correspondent John Blackstone.