RIVERSIDE, Calif. - Five firefighters who died battling an arson wildfire last month faced 90-foot-tall walls of flame that advanced at 40 mph in a terrifying firestorm fueled by howling winds and tinder-dry manzanita and chaparral, according to a new preliminary report.

The six-page report, released late last week by the California Department of Forestry and Fire Protection, indicates that the combination of the wind, the slope of the terrain and the type of ground cover created an explosive fire situation.

Temperatures at the fire's leading edge reached 1,220 degrees and a column of gas and smoke from the blaze rose to 18,000 feet in the air, the report said.

The fire swept through the mountains about 90 miles east of Los Angeles. It destroyed 34 homes and charred more than 60 square miles before being contained.

Firefighters Jason McKay, 27; Jess McLean, 27; Daniel Hoover-Najera, 20; Mark Loutzenhiser, 43; and Pablo Cerda, 23, were overrun by flames on Oct. 26 while protecting a home in Twin Pines.

Authorities have charged a 36-year-old auto mechanic, Raymond Lee Oyler, with arson and murder in the case. He has pleaded not guilty to all charges.

CDF spokesman Daniel Berlant said the report will be used as a teaching tool for future firefighters. He declined to comment further, citing an ongoing internal investigation and the criminal case against Oyler.

The report details the firefighters' actions in the hour leading up to their deaths, including that they were overrun by flames less than an hour after discussing strategies, conditions and safety measures with a superior.

The fire front, fueled by the wind gusts of 50 mph, traveled at almost the exact angle of the slopes below the firefighters, adding to the blaze's spread and intensity.

"It creates erratic, very quick-moving fire behavior," said Rose Davis, spokeswoman for the National Interagency Fire Center in Boise, Idaho. "You have all of the things needed to accelerate the fire - wind, slope and fuel."