The Caldor Fire near Sacramento burned more than 100,000 acres.

Teams battling the Caldor blaze in southwest California’s Lake Tahoe suffered another stressful weekend as the blaze sprawled over more than 30,000 acres in just two days.

The blaze, which began Aug. 14 and grew rapidly, burned 104,000 acres and was 5% contained by Sunday night, according to a New York Times wildfire tracker.

Nearly 350 houses have been destroyed and more than 17,000 structures are threatened by the fire, firefighters said. At least 207 fire engines and 20 helicopters have taken part in the fight against the blaze, requiring more than 1,600 people so far.

Favorable weather conditions may help firefighters at the start of the week – cooler temperatures are forecast in the fire-ravaged areas for Monday and Tuesday, but the same areas are expected to be above normal by Thursday and Friday, said the National Weather Service. Parts of northern California will continue to see smoke and haze from the wildfires.

While forest fires occur every year in the West, scientists are seeing the influence of climate change in the extreme heat waves that have contributed to the intensity of the fires this summer. Prolonged periods of unusually high temperatures are a sign of climate change, they say.

Across California, more than 13,000 firefighters were battling 13 large active wildfires that burned more than 1.54 million acres, according to Cal Fire, the state firefighting agency.

The Dixie fire, the second largest on record in California, remains a threat to communities. It has burned over 720,000 acres since it started over a month ago. It was only 38% content on Sunday night.