A California wildfire exploding through bone-dry timber has prompted Nevada authorities to evacuate a border community as flames leapt on ridgetops of nearby mountains.

The Beckwourth Complex — a merging of two lightning-caused fires in northern California — headed into Saturday showing no sign of slowing its rush north east from the Sierra Nevada forest region after doubling in size a few days earlier.

California Wildfires
The Sugar Fire is part of the Beckwourth Complex Fire (Noah Berger/AP)

The fire is one of several threatening homes across western states that are expected to see fierce heat through the weekend as a high-pressure zone blankets the region.

On Friday, Death Valley National Park in California recorded a high of 54.4C. If verified, it would be the hottest recorded there since July 1913 when the same Furnace Creek desert area hit 56.6C, considered the highest reliably measured temperature on Earth.

California’s northern mountain areas have already seen several large fires that have destroyed more than a dozen homes.

California Wildfires
Firefighters from the California Department of Forestry and Fire Protection (Noah Berger/AP)

Although there are no confirmed reports of building damage, the fire prompted evacuation orders or warnings for hundreds of homes and several campgrounds in California along with the closure of nearly 200 square miles of Plumas National Forest.

On Friday, ridgetop winds up to 20mph combined with ferocious heat as the fire raged through bone-dry pine, fir and chaparral. As the fire’s north-eastern flank raged near the border, Washoe County Sheriff’s Office asked people to evacuate some areas in the rural communities of Ranch Haven and Flanagan Flats, north of Reno.

Hot rising air formed a gigantic, smoky cloud that reached thousands of feet high and created its own lightning, fire information officer Lisa Cox said.

California Wildfires
An air tanker drops retardant to keep the Sugar Fire from reaching the Beckwourth community (Noah Berger/AP)

Spot fires caused by embers leapt up to a mile ahead of the north-eastern flank — too far for firefighters to safely battle, and winds funnelled the fire up draws and canyons full of dry fuel, where “it can actually pick up speed”, she added.

Nearly 1,000 firefighters were aided by aircraft but the blaze is expected to continue forging ahead because of the heat and low humidity that dried out vegetation. The air was so dry that some of the water dropped by aircraft evaporated before reaching the ground, Ms Cox said.

The blaze, which is only 11% contained, had officially blackened more than 38 square miles, but that figure is expected to increase dramatically when fire officials can make better observations.

California Wildfires
Smoke envelops trees in Doyle, California (Noah Berger/AP)

Meanwhile, other fires are burning in Oregon, Arizona and Idaho.

In Oregon, pushed by strong winds, a wildfire in Klamath County grew from nearly 26 square miles on Thursday to nearly 61 square miles on Friday in Fremont-Winema National Forest and on private land. An evacuation order was issued for people in certain areas north of Beatty and near Sprague River.

That fire is threatening transmission lines that send electricity to California, which along with expected heat-related demand prompted California governor Gavin Newsom on Friday to issue an emergency proclamation suspending some rules to allow for more power capacity.

The state’s electrical grid operator also issued a state-wide alert calling for consumers to voluntarily conserve electricity by reducing the use of appliances and keeping the thermostat higher during evening hours when solar energy is diminished or no longer available.

Oregon Wildfires
The Jack Fire burns about 40 miles east of Roseburg, Oregon (Oregon Department of Transportation/AP)

In north-central Arizona, increased humidity slowed a big wildfire that posed a threat to the rural community of Crown King. The 24.5-square-mile lightning-caused fire in Yavapai County was 29% contained. Recent rains allowed five national forests and state land managers to lift public-access closures.

In Idaho, governor Brad Little declared a wildfire emergency on Friday and mobilised the state’s National Guard to help fight fires sparked after lightning storms swept across the drought-stricken region.

Fire crews in north-central Idaho faced extreme conditions and gusts as they fought two wildfires covering a combined 19.5 square miles. The blazes threatened homes and forced evacuations in the tiny, remote community of Dixie, about 40 miles south east of Grangeville.