A series of wildfires have swept across the Texas Panhandle, prompting evacuations, cutting off power, and forcing the temporary shutdown of a nuclear weapons facility.

Strong winds, dry grass and unseasonably warm temperatures fed the blazes in the US state, according to officials.

Republican governor Greg Abbott issued a disaster declaration for 60 counties as the main blaze, the Smokehouse Creek Fire, swelled into the second-largest wildfire in the state’s history.

The main facility that disassembles America’s nuclear arsenal paused operations on Tuesday night, but bosses at Pantex said it was open for normal work on Wednesday.

Authorities have not said what might have caused the blaze, which tore through sparsely populated counties set amid vast, high plains punctuated by cattle ranches and oil rigs.

An unknown number of homes and other structures in Hutchinson County were damaged or destroyed, local emergency officials said.

In Borger, a community of about 13,000 in Hutchinson County, Adrianna Hill said she and her family were terrified as fire encircled the entire town until the winds shifted.

“It was like a ring of fire around Borger, there was no way out … all four main roads were closed,” Ms Hill, 28, said. The flames came within about one mile of the home she shares with her husband and 20-month-old son.

“What saved our butts was that northern wind … it blew (the fire) the opposite direction,” Ms Hill said. “We were scared, but every night I pray … and that’s all I can do.”

Texas Wildfires
Rescuers respond to a fire in the Texas Panhandle (Flower Mound Fire Department via AP)

The Pantex plant, 17 miles north-east of Amarillo, evacuated non-essential staff from the site on Tuesday night out of an “abundance of caution”, according to Laef Pendergraft, a spokesperson for National Nuclear Security Administration’s Production Office at Pantex. Firefighters remained on-site in case of an emergency.

Since 1975 it has been the US main assembly and disassembly site for its atomic bombs. It assembled the last new bomb in 1991 while disassembling thousands.

Authorities have not said what might have caused the blaze, which tore through sparsely populated counties surrounded by rolling plains.

Mr Abbott said: “Texans are urged to limit activities that could create sparks and take precautions to keep their loved ones safe.”

The weather forecast provided some hope for firefighters – cooler temperatures, less wind and possibly rain on Thursday. But for now, the situation was dire in some areas.

Texas Wildfires
The fire doubled in size on Tuesday (Flower Mound Fire Department via AP)

As the evacuation orders mounted, county and city officials live-streamed on Facebook and tried to answer questions from worried residents.

Officials implored them to turn on their phones’ emergency alerts and be ready to evacuate immediately. They described some roads as having fire on both sides and said resources were being stretched to their limit.

Texas state senator Kevin Sparks said an evacuation order was issued for Canadian, a town of about 2,000 about 100 miles north-east of Amarillo.

Later on Tuesday, the Hemphill County Sheriff’s Office urged anyone who remained in Canadian to shelter in place or at the high school gym because roads were closed.

Evacuations were also ordered in nearby Miami, and schools in Canadian and Miami announced closures on Wednesday. East of Canadian, fire officials across the border in the area of Durham, Oklahoma, also encouraged people to evacuate because of the fire.

Evacuations were also happening in Skellytown, Wheeler, Allison and Briscoe, according to the National Weather Service in Amarillo.