Assisted by rising humidity, firefighters gained an upper hand over a massive wildfire which was moving toward Los Angeles, fire commanders said on Tuesday.

The 190-square-mile (304-square-kilometer) Station Fire continued to burgeon, but the rate of increase has diminished, according to the Los Angeles County Fire Department (LACFD).

The U.S. Forest Service reported that fire crews made progress on Monday pushing back flames on the northwestern flank of the blaze.

Firefighters in Glendale and La Canada Flintridge also reported beating back the fire in those areas.

Since its outbreak in the Angeles National Forest north of Los Angeles on Wednesday, the fire has destroyed 53 homes and threatened thousands more in foothill suburbs.

It is also threatening Mount Wilson -- the site of a historic observatory and an array of broadcast communications towers used by the bulk of Southern California's television and radio stations, as well as public safety agencies.

But for the first time in the week, firefighters managed to slow the fire's advance.

"I'm feeling a lot more optimistic today than I did yesterday and the crews are doing fabulous work out there on the grounds but the bottom line is that they're fighting for every foot," said Mike Dietrich of the U.S. Forest Service.

The fire was only 5-percent contained, but Dietrich said the containment figure was expected to rise substantially after overnight progress was mapped.

The U.S. Forest Service had projected full containment by Sept. 8, but on Monday pushed back the date to Sept. 15.

Dietrich noted that bulldozers had carved up to 12 miles (about 19 kilometers) of lines and no new structures were lost overnight.

Even though firefighters have been battling to keep the flames at bay, LACFD Capt. Mark Whaling said fire commanders continue to expect the blaze to burn over Mount Wilson before it is brought under control.

Around 6,000 homes are under mandatory evacuation orders, with authorities recommending voluntary evacuations by the residents of 4,000 others.

The blaze has increased in size since Monday by around 16,000 acres (6,480 hectares) and has now churned through 121,762 acres (about 49,314 hectares), LACFD Capt. Mark Savage said this morning.

But the rate of increase was sharply lower than the day before, when the blaze grew overnight by more than 43,000 acres (17,415 hectares), he said.

Fire commanders said the rate of increase diminished thanks to a rise in humidity, beginning around 6 p.m. Monday. Rising humidity also enabled firefighters to report some progress on Monday in fighting the blaze, especially on ridge tops.

National Weather Service forecasters said they expected a 10-15 percent rise in humidity, taking it to around the 25-percent level on Tuesday.

"When you're fighting a forest fire, even a one-percent rise helps," said National Weather Service meteorologist Andrew Rorke.

The Station fire is the largest of several in California, extending from the Pasadena area to the high desert. It has spread nearly 20 miles (32 kilometers) from north to south and about 25 miles (40 kilometers) from east to west.

At least 3,655 firefighters are being deployed to fight the blaze, along with 399 fire engines, five helicopters, eight helitankers, 10 air tankers, 58 hand crews and 48 bulldozers.

(Xinhua News Agency September 2, 2009)