Firefighters are close to completing containment lines around the remnants of the huge wildfire that scorched two Southern California counties this month and added to the state's enormous bill for fighting wildland blazes.

The so-called Thomas Fire was 91 percent contained Thursday, with remaining active heat sources well inside the perimeter of the 440-square-mile burn area northwest of Los Angeles, the state fire summary said.

Firefighter activities were described as mop-up and patrol.

The fire erupted Dec. 4 in Ventura County and quickly became a wind-driven inferno, destroying 1,063 structures and damaging 280 others as it swept through rural agricultural lands, into the city of Ventura and into neighboring Santa Barbara County where it finally was tamed when gusts faded away.

By late this month, firefighting costs topped $174 million as the wildfire became California's largest on record and more than 8,000 firefighters were on the lines. The number has since dwindled to fewer than 700.

The Los Angeles Times reported that only halfway through the state's current fiscal year, the California Department of Forestry and Fire Protection has already spent $699 million battling wildland blazes, including the deadly October firestorms that devastated wine country communities and other parts of Northern California.

That tops Cal Fire's budgeted amount for firefighting by $272 million with six months left in the fiscal year, the Times said.

Whether tallied in acres or dollars, it's all part of a trend of year-round fire seasons that scorch larger and larger amounts of land and eat up firefighting budgets.

In September, the U.S. Forest Service said it had spent more than $2 billion on wildfires in the just-ended federal fiscal year. That topped the previous record of $1.7 billion set in 2015.