Blaze in Northern California grows and destroys 20 homes

Fire officials say a wildfire burning near the Northern California town of Oroville has destroyed 20 homes.

The California Department of Forestry and Fire Protection says the blaze about 70 miles (112 kilometres) north of Sacramento had consumed nearly 6 square miles (15 square kilometres). It's threatening 500 homes.

Fire crews increased containment to 30 per cent overnight ahead of a statewide heat wave.

But officials say the fire's location in steep and rugged terrain plus hot and dry temperatures are complicating firefighters' efforts.

More firefighters are joining the more than 1,600 already battling the fire.

The blaze is one of many wildfires across the US West, including fires in and around California's Yosemite National Park that have closed a popular road into the park prompted evacuations of nearby towns.