Thousands evacuate as fast-moving wildfire threatens Reno, Nevada

The Hawk Fire began on Saturday and grew to more than 23 square miles as it spread on Sunday (Cari Kieffer via AP)

Authorities in the US were urging some 90,000 residents to evacuate as shifting winds continued to challenge firefighters trying to bring an out-of-control wildfire in Nevada under control.

The blaze jumped over fire engines and made it difficult for crews to reach destroyed homes in north-west Reno on Sunday.

At least six people — three emergency services personnel and three civilians — were injured.

Officials said the fire was “human-caused” but did not provide details about how they had reached that conclusion, or whether it was intentionally set or accidental.

The Hawk Fire began on Saturday and grew to more than 23 square miles (60 sq km) as it spread on Sunday across the Peavine Peak area of the Humboldt–Toiyabe National Forest, where rugged foothills are ringed by homes and businesses near the California state line. There was zero containment.

Some 42,000 residents have been ordered evacuated as the “Go Now” zone expanded, reaching the edge of the University of Nevada.

An additional 45,000 people were in the adjacent evacuation warning zone.

Authorities urged people to be prepared to stay away for several days, because shifting and strengthening winds were expected to make the fire even more unpredictable.

“Please get out if you can right now,” Washoe County sheriff Darin Balaam said.

A Sunday evening update said crews observed “extreme fire behaviour” as gusts pushed flames through dry brush.

“Over the next 12 hours, the fire is expected to continue to make moderate to high intensity runs in pockets of dense fuels,” the statement said.

It was not known how many homes were destroyed.

Cari Kieffer said a video posted on social media showed her house entirely burned down, with only a scorched basketball hoop still standing.

“I woke up this morning and just started crying — all my kids, they lost everything,” Ms Kieffer said on Sunday.

“We lost all our stuff. Everything we own is gone.”

Nevada governor Joe Lombardo declared a state of emergency in Washoe County and mobilised the Nevada national guard to support aerial firefighting with two helicopter crews as well as 60 troops to help police safeguard evacuated neighbourhoods.

Also responding were 800 fire personnel.

Nearly 10,000 customers were without power in Washoe County on Sunday, down from 60,000 on Saturday.

Portions of US Route 395, a major north-south road, were closed because of the fire.

Reno, with more than 280,000 residents, is the largest city in Nevada outside of metro Las Vegas.