The Thomas Fire in California's Ventura and Santa Barbara counties has consumed more than 230,000 acres over the past week — becoming the fifth largest fire in the state's history and continuing to send firefighters scrambling to control the blaze, officials said on Monday.

Crews had 20 percent of the fire under control as of Monday night, up from the 10 percent reported contained on Sunday night, according to state fire officials.

At a community meeting in Santa Barbara, officials offered a sliver of optimism: the fire grew by only 500 acres on Monday, they said, a development aided by good weather and air tankers that were able to drop fire retardant.

And in the city of Ventura, where more than 100,000 people live and 138 buildings were destroyed, nearly all mandatory evacuations were lifted on Monday afternoon, according to the California Department of Forestry and Fire Protection, or Cal Fire.

Photos: California Coast Battles Massive Wildfire

The fire began on Nov. 4 as a Santa Ana wind-driven brush fire and morphed into a massive wildfire — stoked by high winds and feeding on tinder-dry conditions — that thousands of firefighters are still battling as of Monday afternoon.

Five fires covering more than a quarter of a million acres continue to rage across Southern California, with 9,000 firefighters combating the flames, Cal Fire said. Roughly 257,000 acres have burned and destroyed more than 1,000 structures.

However, the Thomas Fire has far surpassed the damage of the other blazes. It has threatened 18,000 homes and sent 95,000 residents fleeing, officials said. It has already destroyed nearly 800 structures and damaged 187 others, according to Cal Fire.

Firefighters move away from a burning house after discovering downed live power lines near Carpinteria. Mark Ralston / AFP - Getty Images

Among those to lose a home was Ventura resident Antonio Wong, whose home burned last Tuesday. Wong's previous house, in Santa Rosa, was destroyed during a series of fires that tore across the state's wine region two months ago, killing 42 people and razing more than 8,000 buildings.

Wong lived in his Ventura home between 2002 and 2008. He kept it through a series of moves, opting instead to rent it out rather than selling.

"We're still in shock," Wong said in an interview with NBC News. "I don't even know if I've fully processed the Ventura fire yet because I was still trying to process the first fire."

Related: ‘Like an Atom Bomb Hit’: Santa Rosa Residents Confront Devastation

In Santa Barbara, the county sheriff's office issued evacuation orders on Sunday for the area spanning Buena Vista Drive to Toro Canyon Road from SR-192 north to Camino Cielo. Authorities also issued mandatory evacuation orders for localities in Ventura County, including the City of Ventura, Ojai, Rose Valley, and the unincorporated area of Fillmore.

Officials said fire weather could set off more blazes in the region, particularly the Santa Barbara communities of Montecito and Summerland. Gusty Santa Ana winds could push the blaze west and very low fuel moistures, which indicates fire potential, along with high temperatures and low humidity could ignite potential fires on the west and north sides, authorities said.

Firefighters watch after setting a backfire at night to make progress. David McNew / Getty Images

And while some residents have been able to go back to evacuated homes, officials warned that there are residual dangers.

"When you are able to return home after a wildfire, it doesn’t mean that all of the danger is gone,' Cal Fire said in a statement. "Fire damage on your property and the surrounding area has more potential hazards than you might think."

California fire officials offered a webpage with tips for staying safe.