The state is currently fighting multiple wildfires, and is experiencing a heatwave. (AP: Noah Berger)
A pair of wildfires in the United States have quickly spread, threatening hundreds of homes in California and forcing evacuations at a popular lakeside campground and a summer camp.
The fire that started this weekend in California’s Santa Barbara County was “completely out of control,” county fire Captain Dave Zaniboni said.
About 90 children and 50 summer camp counsellors found themselves stuck at one ranch, and had to take shelter there until they could be safely evacuated.
The Santa Barbara County fire was one of three fast-growing blazes in California.
High temperatures and dry gusts tripled the size of another Santa Barbara wildfire to around 77 square kilometres over eight hours and forced evacuations of about 200 homes in a rural area east of Santa Maria, fire spokesman Kirk Sturm said.
After five years of severe drought, California got a big break with record rainfall and snowpack in parts of the state this year that has delayed the start of fire season in some places, but has also led to explosive vegetation growth that could fuel future fires.
In Northern California, a Butte County wildfire swept through grassy foothills and destroyed 10 structures, including homes, and led to several minor injuries.
The blaze about 97 kilometres north of the city of Sacramento grew rapidly to nearly 11 square kilometres and was 20 per cent contained, according to the California Department of Forestry and Fire Protection.
The area burning was about 16 kilometres south of Oroville, where spillways in the nation’s tallest dam began crumbling from heavy rains this winter and led to temporary evacuation orders for 200,000 residents downstream.
In other parts of the country’s west, evacuation orders were lifted in Colorado and Montana towns threatened by wildfires, while air and ground crews battled a growing grass fire in north-western Colorado.
Much of California has baked in extreme heat, with a 131-year-old weather record in Los Angeles breaking when the temperature spiked at 36.7 degrees downtown.
Potentially dangerous temperatures will be common in some parts of California. (AP: Noah Berger)
The previous record of 35 degrees was set in 1886, the National Weather Service said.
Forecasters warned that temperatures of up to 43 degrees would be common in some inland areas and could be deadly for the elderly, children and outdoor workers.
Air quality reached unhealthy and very unhealthy in areas inland from Los Angeles.