SANTA BARBARA, CALIF., JUNE 29 -- Firefighters began to gain the edge today on wildfires that stormed across six Southern California counties, killing a Santa Barbara County woman and an inmate-firefighter and destroying more than 500 houses and other buildings.

Arson was blamed for many of the fires that have scorched more than 20,000 acres in Santa Barbara, San Bernardino, Los Angeles, Orange, Riverside and San Diego counties since Wednesday.

"Whoever started this fire is, in my opinion, not only a terrorist, but a murderer," said Rep. Robert J. Lagomarsino (R-Calif.), whose district includes Santa Barbara.

Elsewhere across the West:

A fire started by lightning in Arizona's Tonto National Forest was about 50 percent contained. Six firefighters died in the blaze that burned 24,000 acres and 50 houses.

A 4,020-acre blaze in Guadalupe Mountains National Park in Texas slowed its spread but remained out of control.

Colorado firefighters worked to stop a 3,160-acre fire in the Uncompahgre National Forest.

The body of Andrea Gurka, 37, was found this morning in a creek bed behind her home near where the Santa Barbara fire was started by an arsonist, Charlie Johnson, a county fire spokesman, said. "She apparently had attempted to flee her residence when it was being overrun by flames Wednesday evening," he said.

Victor Ferrara, imprisoned for assault with a deadly weapon, died of burns suffered while fighting a fire in Riverside County about 65 miles east of Los Angeles, said Karen Terrill of the California Department of Forestry. He was among 16 inmate-firefighters overrun by a wildfire.

Fifteen other firefighters were injured when the 150-acre blaze overran them. Four remained hospitalized, one in critical condition.

California's inmate-firefighting program began in 1946, and the first fatality occurred last year. The state prison system and state Department of Forestry and Fire Protection jointly operate the program.

The inmates benefit "by developing an esprit de corps that they've never had before, except maybe in gangs," said Lt. D.M. Reynolds, a program spokesman. "They become a team. It teaches them the work ethic."

The 1,200 inmates on fire lines today are among 3,700 housed at 40 conservation camps throughout the state, where they do other manual labor when not fighting fires. About 300 are women who work in segregated crews.

U.S. Forest Service spokeswoman Juanita Freel estimated that the 4,900-acre Santa Barbara fire would be contained Saturday by the 1,700 firefighters on the line.

More than $200 million damage to structures was caused by the fire, said Frank Breckenridge, a county building official. He said 417 homes, 28 apartments, 10 businesses and four public buildings were destroyed in Santa Barbara County.