It has been several days since two huge wildfires in Northern California peaked in their ferocity, yet the damage they did is still being revealed daily.

The tally of homes destroyed topped 1,000 on Saturday after authorities assessing damage in the Sierra Nevada foothills counted another 250 houses destroyed by flames still threatening thousands of more structures.

"Some of the homes are tucked back in rural areas, so it's taken time to reach them," state fire spokesman Daniel Berlant said.

The new count of 511 homes destroyed by one of the blazes — up from 252 a day earlier — comes as firefighters make significant progress against it.

The fire, which killed at least two people, was 67 percent contained. Another 6,400 structures remain under threat.

A separate blaze in Lake County, about 170 miles northwest, has destroyed 888 structures, at least 585 of them homes. It has killed three people.

Residents of Middletown, the area hardest hit by the massive wildfire in California, were allowed to return home Saturday afternoon. Evacuation orders for other areas in Lake County remained.

The Lake County fire tore through 62 square miles in 12 hours, causing thousands of residents to flee after it ignited a week ago. About 19,000 people were ordered to evacuate. The blaze had charred 116 square miles and was 50 percent contained Saturday.

A weekend of heat had descended on the wildfires after several favorable days, raising fears that major gains could be undone.

"We're looking at predicted weather of 100 degrees for the next couple of days, and at least mid-90s throughout the weekend," Scott Mclean, a battalion chief with the California Department of Forestry and Fire Protection, said Friday.

That makes it essential that the smoldering remains of the two giant blazes be dealt with as quickly and thoroughly as possible, Mclean said.

"You've got some high temps, high winds that could stir up those ash piles and those ember piles," he said. "We have to do that mop-up to be sure this fire goes to bed."