The fire broke out Thursday evening on the 21000 block of south Avalon Boulevard and then spread to a mobile home park.
Officials said more than 100 firefighters battled the fire. Investigators were still on scene Friday morning trying to determine the cause of the massive blaze.
The planned 150-unit luxury apartment building was set to open July 2012.
The inferno engulfed much of the wooden complex within moments. Flames shot 100 feet in the air and could be seen from the San Fernando Valley.
Firefighters said the all-wood frame accelerated the fire and it spread quickly. The heat was so intense that it blew out windows of many nearby cars and even melted the paint off of some fire trucks.
The intense heat combined with wind gusts sent the fire into the nearby Park Avalon Mobile Estates. More than 139 mobile homes had to be evacuated.
Evacuated residents were allowed to return home Friday afternoon. Unfortunately, five mobile homes were destroyed.
"I can't explain it to you, except that this is the worst kind of emergency I had in my 89 years," said resident Angeles Mercado.
Mercado said his home for the last 15 years was destroyed, and all he could salvage was put into the back of a relative's minivan.
"When the policeman pulled me out, the fire was there at the back already," said Mercado.
Two mobile homes down, Don Goodhart was assessing the damage to his 3-year-old home. He said the damage is about $200,000.
"Frustrated and don't know where to go and don't know what to do," said Goodhart.
Many residents who were just yards away from the fire said it was a race to get out.
"It looked like a total wreck, like a house of cards or a book of matches getting caught on fire. It went up that fast, like in about 20 seconds from like zero to 60. I couldn't believe it, that fast. We had to get out of there," said Gene Brown, who lived in the apartment complex.
Park Avalon Mobile Estates resident Belinda Rich said she has never seen a fire like this in her life.
"It was just panic. Everybody was running out crazy, making sure all the neighbors got out," said Rich.
L.A. County Fire Capt. Mark Savage said the fire could have been much worse if Mother Nature wasn't on their side.
"If we would have had a Santa Ana wind that was predicted or expected, moderate Santa Ana winds 15, 20, 30 mile-an-hour winds, this would have been a different situation," said Savage. "Stopping the spread of that fire would have been much more difficult."
Eleven mobile homes were severely damaged by the fire. Despite the damage, there were no injuries, and residents who felt the terror and feared the worst are thankful no lives were lost.
"Just get out. At that point, I didn't care [about] money, nothing, just leave, you know? As long as you're alive, then you have your life with you," said Park Avalon Mobile Estate resident Griselda Pena.