A 516-acre brush fire in Calabasas that resulted in 5,000 residents being evacuated Saturday was sparked by a solo-vehicle car crash, according to the Los Angeles County Fire Department.
Remnants of the so-called "Old Fire" were still burning late Sunday evening, after hundreds of firefighters worked through the day to gain control over the massive blaze.
Crews were getting a handle on it, as containment increased from 75 percent to 80 percent by 5 p.m., the Fire Department's Deputy Chief John Tripp announced at a news conference.
"With the hundreds of homes that we had in threat, the fact that we had no damage (to homes) is definitely a very positive effort by the residents of Calabasas and Topanga," he said, "and also, of course, the the firefighters that were in there trying to save those structures."
Officials initially said two residences were damaged in the fire, and one commercial structure was destroyed. The Fire Department later confirmed that four structures -- two access bridges and two sheds -- were destroyed.
All evacuation orders and road closures were lifted at 6 p.m., the agency said.
The destructive blaze began 4 p.m. Saturday when a vehicle crashed into a power pole in the 2300 block of Mulholland Highway, according to Supervisor Melanie Flores of the Fire Department.
"Witnesses reported that the truck was traveling at a high rate of speed before colliding into a power pole, causing the pole to fall and a transformer to explode, thus igniting the Calabasas fire," Deputy Jeffrey A. Gordon with the Los Angeles Sheriff's Department told CNN.
Information about the driver has not been provided.
The growing fire scorched more than 500 acres as high temperatures hit the area Saturday. By the following morning, crews were making progress as containment doubled overnight.
At early morning news conference, L.A. County Fire Inspector Edward Osorio cautioned that figure could change throughout the day.
“That number will fluctuate as the acreage goes up or down, and as the day progresses," he said.
The fire triggered a multi-agency response, with 400 firefighters from the fire departments of L.A., Ventura and Orange counties, the city of Los Angeles and Cal Fire being sent to the area to battle the flames.
Temperature were expected to be 90 to 95 degrees Sunday, which was slightly cooler than the previous day. Humidity was at 15 percent, while light winds of 10 to 15 mph were pushing the flames in a westerly direction, according to Osorio.
“The plan for now is to get a jump on the fire, try to make the majority of our progress early this morning while temperatures are cool, and prevent the fire from reaching the point where it will become more active … between the 12 o’clock and 4 o’clock hour," he said.
At one point, 3,700 homes were evacuated, impacting some 5,000 residents, authorities said Sunday morning.
Mandatory evacuations had been ordered for four of the so-called "tactical zones" in the area hours after the flames erupted, while voluntary evacuations were in effect in two other zones. (Click here to see the map)
By 2 a.m. Sunday, the evacuations had been lifted in the Calabasas area, and residents were allowed back to go back to their homes, according to a tweet from the county Fire Department.
The areas included Eddingham and Adamsville avenues, and the Calabasas Highlands neighborhood.
However, fire officials warned that power was out at many of those residences, and encouraged displaced residents to stay with friends or relatives, if possible.
Southern California Edison crews were working to restore service to impacted customers.
“The reason being is we have a lot of potential unburned fuels in that particular area, that if the weather were to change on us, or get extremely hot, extremely fast, we can have a very dynamic situation," said Osorio.
An evacuation center for displaced residents was established at Agoura High School in Agoura Hills (map).
Old Topanga Canyon Road, Topanga Canyon Boulevard and the Mulholland Highway were temporarily closed to the public, though Topanga Canyon was accessible by residents, authorities said.
Three firefighters have been injured battling the blaze; all of the injuries were considered minor.
A smoke advisory was issued in the San Fernando and Santa Clarita valleys, and in surrounding areas, because of the fire, according to the L.A. County Department of Public Health.
Individuals in those parts were urged to avoid unnecessary outdoor exposure and to limit physical activity.
KTLA's John A. Moreno contributed to this report.