By Steve Gorman
LOS ANGELES (Reuters) - Crews battling a devastating California wildfire that now ranks as the state's second-largest on record capitalized on a third straight day of favorable weather conditions on Tuesday as they made greater progress corralling the flames.
With the so-called Thomas fire blazing into its third week in the coastal mountains, foothills and canyons of Ventura and Santa Barbara counties northwest of Los Angeles, officials scaled back evacuation orders, sent home some visiting firefighters and reported improved air quality.
"I would definitely say things are looking better today than they have in the last two weeks," Rudy Evenson, a spokesman for the incident command center, told Reuters by telephone.
Higher humidity, combined with diminished winds and temperatures to ease firefighters' jobs since Sunday, but the region remains "critically dry," a group of agencies said in a statement.
More than 1,000 homes and other buildings have gone up in flames and about 18,000 structures remained listed as threatened from a late-season firestorm that kept crews on the defensive for the better part of two weeks.
One firefighter died last Thursday near the town of Fillmore in Ventura County.
Still, fire managers are "cautiously optimistic" of having gained sufficient ground this week to protect populated areas against the return of high winds forecast for Wednesday night and early Thursday.
"We feel pretty confident about that for now," Evenson added.
By Tuesday night, firefighters had carved containment lines around 55 percent of the blaze's perimeter - up from 50 percent earlier in the day. But the fire has still spread by several hundred acres a day since the weekend.
In total the fire has scorched 272,000 acres (110,074 hectares) of drought-parched chaparral and brush since igniting on Dec. 4, covering an area equivalent to nearly a third of Rhode Island.
The latest tally makes the Thomas blaze one of the two largest single wildfires documented in California, second only to the 2003 Cedar fire in San Diego County, which consumed a record 273,246 acres (110,600 hectares) and killed 15 people.
The Thomas fire was initially stoked by hot, dry Santa Ana winds blowing with rare hurricane force from the eastern desert, spreading flames across miles of rugged coastal terrain faster than firefighters could keep up.
Winds have briefly abated a few times since, but the latest three-day break in the weather marked the most welcome relief offered firefighters yet by Mother Nature.
As a measure of their progress, officials have begun demobilizing crews, cutting the firefighting force to just over 6,800 personnel from about 8,500.
The cost of fighting the blaze runs into more than $150 million, the California Department of Forestry and Fire Prevention estimates. The cause is still being investigated.
The Thomas fire erupted two months after a spate of wind-driven blazes in Northern California's wine country destroyed several thousand homes and killed more than 40 people. That ranked as the deadliest rash of wildfires, and one of the most destructive, in state history.
(Additional reporting by Sharon Bernstein in Sacramento and Peter Szekely in New York; Editing by Frances Kerry and Clarence Fernandez)