California faces fire, flood threats

·2-min read

Forces have begun to collide in California as wildfires threatened communities, an epic heat wave stressed the electrical grid and as moisture from a tropical storm was expected to bring thunderstorms and floods along with cooling.

Firefighters struggled to control major wildfires in southern California and the Sierra Nevada that have grown explosively, forced extensive evacuations and produced smoke that could interfere with solar power production.

The Fairview Fire in southern California covered about 95 square kilometres of Riverside County on Thursday and was just five per cent contained.

Two people died while fleeing flames on Monday and at least 11 structures have been destroyed.

More than 18,000 homes were threatened by the fire fed by shifting winds, officials said.

In the Sierra, the Mosquito Fire burned out of control, scorching at least 28 sq km, forcing evacuations for some 2500 residents in Placer and El Dorado counties while blanketing the region in smoke.

Flames jumped the American River, burning structures in the mountain hamlet of Volcanoville and moving closer to the town of Foresthill. Fire spokesperson Chris Vestal called the fast-moving blaze an "extreme and critical fire threat".

The fire's cause remained under investigation.

Another dangerous blaze burned in stands of timber near the Big Bear Lake resort region in the San Bernardino Mountains east of Los Angeles. It was just two per cent contained after scorching nearly 5 sq km).

A surge of clouds and showers associated with Tropical Storm Kay off Mexico's Baja California peninsula knocked the edge off temperatures in southern California at times. The storm was downgraded from a hurricane on Thursday evening.

Despite the initial impacts of Kay, forecasters warned the heat was not yet done.

"The seemingly endless heat wave that has been plaguing California will finally becoming to an end across at least southern California, but not before two more very hot days and very warm nights," the Los Angeles-area weather office wrote.