As of 5:30 a.m. Sunday, the blaze had charred 1,906 acres, and was 78 percent contained. Despite progress, officials pushed the blaze's estimated containment time from Sunday to Wednesday.
Residents forced to flee were allowed to return around 6 p.m. Saturday as crews gained ground on the massive blaze burning the foothills.
The blaze erupted around 5:50 a.m. Thursday in the Angeles National Forest near Glendora Mountain Road and Colby Way. Flames spread rapidly and moved down the hill toward homes, forcing 3,700 people to evacuate.
Glendora residents were allowed back in their homes Thursday night, but some Azusa residents were still evacuated Friday. Evacuation orders were lifted at 4 p.m. Friday between Ranch Road and Yucca Ridge Road, including the Crystal Canyon Condo Complex and the Mirador Housing Tract, in Azusa.
Evacuation orders for Mountain Cove residents were lifted around 6 p.m. Saturday. Residents were advised to remain on alert for rocks falling on the roadway.
Temperatures were in the 80s with very low humidity, but wind gusts were not expected to top 15 miles per hour and Red Flag Warnings were slated to expire at 6 p.m.
"Everything is fluid," said Nathan Judy of the U.S. Forest Service, adding that firefighters set backfires Saturday and worked to extend and fortify containment lines. "We have to get boots all the way around this fire to call this thing completely out."
About 1,175 personnel were on the fire lines, along with nine helicopters and two SuperScooper aircrafts.
The Colby Fire destroyed five homes and damaged 17 buildings. One of the homes destroyed by flames was a guest house on the campus of the historic Singer Mansion, a 1920s Spanish estate built by heirs to the Singer sewing machine fortune on Kregmont Drive.
Three injuries were reported from the fire. Authorities say a civilian and a firefighter suffered minor burn injuries, and a another firefighter suffered a minor ankle injury.
Three men suspected of recklessly starting the Colby Fire will face federal charges, a spokeswoman for the Los Angeles County District Attorney's Office confirmed to Eyewitness News Friday. The men -- identified as Clifford Eugene Henry, Jr., 22, of Glendora; Jonathan Carl Jarrell, 23, of Irwindale; and Steven Robert Aguirre, 21, a transient last known to live in LA -- were taken into custody Thursday after two of them were seen running from the mountains.
The American Red Cross shelter located at Glendora High School at 1600 E. Foothill Blvd. in Glendora was closed Saturday. Evacuation centers that were set up at Memorial Park in Azusa and the Duarte Community Center have also been closed.
The Red Cross is working with evacuees still in need of accommodations, and is prepared to reopen the shelter, should the need arise.
Individuals and families who have emergency disaster-caused needs were urged to call (855) 891-7325.
Evacuated pets can be brought to the Pasadena Humane Society, 361 S. Raymond Ave; the Inland Valley Humane Society, 859 E. Sierra Madre Ave., or Memorial Park in Azusa, 320 N. Orange Place. A shelter for evacuated horses has been set up at the Pomona Fairplex, Gate 12, 1101 W. McKinley Ave.
Officials said evacuated animals that were taken to the Los Angeles County Animal Care and Control's evacuation trailers are being transported to the Baldwin Park Care Center located at 4275 N. Elton St. in Baldwin Park.
All streets north of Sierra Madre Avenue from Glendora Mountain Road to Yucca Ridge were closed. Highway 39 and Glendora Mountain Road are shut down and open to residents only. Azusa Police has closed the Garcia Trail.
San Gabriel Canyon Road was closed above the community of Mountain Cove.
With winds calming down and stagnant air, the heavy smoke from the Colby Fire is prompting all kinds of air quality warnings.
The Los Angeles County Health Department urged individuals to take precautions when outdoors in area where there may be visible smoke or an odor of smoke.
Air quality was deemed unhealthy for sensitive individuals in the San Gabriel Valley and Pomona area. People in affected areas were urged to stay indoors with air conditioning.
CNS contributed to this report.