REDDING (AP) — A major Northern California wildfire that once threatened thousands of homes and led to a massive evacuation could be fully contained by late Wednesday, officials said.

Firefighters are expected to get the Ponderosa Fire under control as nearly 1,700 firefighters mop up some of the remaining hot spots, state fire spokeswoman Julie Hutchinson said.

The anticipated containment comes after a red flag warning due to high winds and low humidity was lifted earlier in the day.

"We're this close," said Hutchinson adding that it could take several more weeks before the fire is extinguished.

Located about 25 miles from Redding and 150 miles north of Sacramento, the blaze has consumed more than 43 square miles and has destroyed more than 142 structures since it started burning nearly two weeks ago.

Meanwhile, evacuation orders remained in effect for about 300 residents in northwest Siskiyou County as the fast-moving Goff Fire continues to threaten about 80 homes in Seiad Valley.

More than 600 firefighters are managing to control the blaze so far, said fire spokesman Duane Lyon. The fire is 16 percent contained.

"We're trying to meet it head-on as the fire is trying to come down the slope," said Lyon as crews have been placing strategic fires to reinforce containment lines. Choppers are also on the scene dropping flame retardant and water to get the fire corralled, Lyon added

Also Wednesday, more than 1,800 firefighters and nearly three-dozen helicopters continue to battle the North Pass Fire northeast of Covelo in Mendocino County. The blaze is now 35 percent contained after burning more than 51 square miles since it was sparked by lightning nearly two weeks ago.

Crews are trying to reach active portions of the blaze by trekking through rugged wilderness, said fire spokeswoman Elizabeth Souza.

Smoke from the fire on Tuesday triggered the Shasta County Air Quality Management District to issue an air quality advisory warning those with respiratory ailments to stay indoors.