While Caldor Fire slows and evacuation orders are lifted, three new wildfires erupt in California - CNN

(CNN)Firefighters in California made significant progress against the Caldor Fire over the weekend, allowing for some evacuation orders in the Lake Tahoe region to be downgraded. But as residents there began to breathe a sigh of relief, three new fires ignited in the state Sunday, according to Cal Fire.

Evacuation orders for the city of South Lake Tahoe were downgraded to evacuation warnings Sunday, nearly a week after thousands in the resort town clogged roadways when officials told them get out because flames were racing into the area.

Other parts of El Dorado County saw their evacuation orders downgraded to a warning Saturday while other warnings were lifted, according to Cal Fire.

The areas of Fallen Leaf Lake, Christmas Valley, Meyers, and North Upper Truckee remain under an evacuation order.

Across the state border in Nevada, mandatory evacuations in Douglas County were downgraded to precautionary evacuations Saturday, according to an announcement on the county's website, opening the door for some residents there to return home.

As of Sunday evening, the Caldor Fire had consumed 215,400 acres near the California-Nevada border. The flames are 44% contained about three weeks after it started on August 14, Cal Fire said.

While still massive, the Caldor Fire's growth slowed over the weekend, adding just 842 acres in a 24-hour period between Friday night and Saturday night, according to CNN's analysis of fire information. That's a far cry from its explosive start, when the fire grew to nearly 100,000 acres in its first week.

High temperatures ahead

Saturday night, fire behavior in the Caldor Fire's East Zone was "minimal to moderate," Cal Fire said in an update Sunday evening.

"There is still much work to be done tying in dozer lines and holding along the south and southeast flank of the fire above Caples Lake. However so far, firefighters are making good progress," the report said.

As firefighters measure their progress, they are also keeping an eye on the forecast as another heat wave is shaping up for this week.

Nearly 25 million in California, Nevada, and Arizona will experience temperatures up to 20 degrees above average, meaning the region could see 105 to 115 degrees, CNN meteorologist Michael Guy said. The majority of the heat will impact the desert Southwest.

At the same time, a Red Flag Warning is in effect for portions of central Oregon and central northern California Tuesday, meaning conditions will be optimal for fire to spread, Guy said.

In the meantime, fire officials urged those returning to their homes to do so safely and keep an eye on updates.

"Repopulation consists of complex coordination between, fire, law enforcement, public works, and utilities to ensure the safety of residents and fire responders alike," Cal Fire said.

The Caldor Fire has destroyed more than 900 structures since it began, including homes, business and other buildings, Cal Fire said. More than 27,000 structures are threatened.