REDDING, Calif. >> Hundreds of firefighters worked today in high heat to beat back three large wildfires in the forests of far Northern California, where the flames destroyed several homes and forced some communities to evacuate.

Mount Shasta, the volcano that towers over the region, was shrouded in a haze from smoke plumes that could be seen in images from weather satellites in space.

The scene was ominously reminiscent of last year’s California wildfire season, which scorched more than 6,562 square miles (17,000 square kilometers) of land, the most in the state’s recorded history.

An extraordinary Pacific Northwest heat wave that extended into the upper reaches of California was slowly receding, but it was only expected to cool off slightly before temperatures trend back up heading into the Fourth of July weekend, forecasters said.

“It is very hot and dry,” said Suzi Johnson, a Shasta-Trinity National Forest spokeswoman for the Salt Fire, which broke out Wednesday and grew to 7 square miles (18 square kilometers), shutting several lanes of Interstate 5 and prompting evacuation orders for some roads in Lakehead, an unincorporated community of around 700 people.

A reporter for the Redding Record Searchlight saw at least a dozen buildings destroyed south of Lakehead, including homes, garages and outbuildings, the paper reported.

Johnson told the paper that investigators were trying to locate a car that may have started the fire Wednesday afternoon near Interstate 5 when hot pieces or parts apparently flew off and ignited dry brush.

About 300 firefighters battled the blaze but were hampered by hot weather and challenging terrain, officials said.

The fire was a threat to homes around Shasta Lake north of the city of Redding, more than 200 miles (322 kilometers) north of San Francisco. The huge lake is popular with vacationers, but its water level is dramatically low because of the drought.

No building damage was reported from two other northern fires, which erupted as California and the rest of the U.S. West was mired in a historic drought tied to climate change.

To the north, the Lava Fire burning partly on the flanks of Mount Shasta grew to nearly 31 square miles (80 square kilometers) and was 25% contained. Evacuation orders for communities near the city of Weed were still in effect.

The steep, rocky terrain challenged nearly 1,300 firefighters battling the blaze, which was ignited by lightning last week.

To the northeast, the Tennant Fire that broke out Monday in the Klamath National Forest and forced evacuations grew to about 15 square miles (38 square kilometers). The fire was expected to advance north toward Oregon, and its cause was being investigated.

Many of California’s national parks have restrictions on campfires, cooking and smoking because of fire risks in the hot, dry summer. The parks are bracing for large crowds over the holiday weekend.

Fire authorities throughout California also have stepped up campaigns urging people not to use fireworks to celebrate the Fourth of July, citing both the explosive dangers and the threat of wildfires in the withering conditions.

“The fuels are bone dry,” Los Angeles County Fire Chief Daryl Osby said at a news conference. “We are extremely concerned about the use of fireworks of all kinds.”