As snow showers moved across the Texas Panhandle on Thursday, easing conditions for firefighters, a wildfire grew into the state’s largest on record, with fears it could again spread rapidly when hot and windy weather returns this weekend.

The Smokehouse Creek Fire had burned 1,050,000 acres in Texas by early Thursday morning, and it had also spread across 25,000 acres into Oklahoma, the Texas A&M Forest Service said. Another fire, the 687 Reamer Fire, had also spread into the footprint of the Smokehouse Creek Fire.

The fires killed one person, an 83-year-old woman in the town of Stinnett, Texas, the Associated Press reported. In Hemphill County, which includes the city of Canadian, there were no reports of anyone unaccounted for, the Canadian Record posted on Facebook, but Texas A&M extension officials shared images on social media of destroyed homes and singed farmland, saying homes had been destroyed and thousands of cattle lost there.

The Forest Service warned that any new ignitions in the coming days could cause the situation in northern Texas to worsen.

“Strong winds and warm temperatures have resulted in grasses drying across many portions of Texas,” Wes Moorehead, Texas A&M Forest Service fire chief, said in a statement. “As firefighters continue to suppress active fires, we urge Texans to be cautious with any outdoor activity that may cause a spark.”

Opening his remarks focused on immigration policy in a visit to Texas’s southern border, President Joe Biden made clear his concerns that global warming has heightened the potential for such devastating fires.

“I love some of my Neanderthal friends who think there is no such thing as climate change,” Biden said.

Despite cold temperatures and light snow, firefighters battled at least one structure fire and power lines ablaze early Thursday, the Canadian Record reported. The Smokehouse Creek Fire tore through the Canadian area, which is northeast of Amarillo, on Tuesday and Wednesday, and by Thursday morning remained 3% contained, the Forest Service said.

The National Weather Service reported snow across the Panhandle region on Thursday, from Amarillo to Borger, 40 miles to the northeast, near where the Smokehouse Creek Fire ignited Monday and other blazes were still burning. The Windy Deuce Fire west of Borger had burned 142,000 acres and was 50% contained as of Thursday evening, up from 30% containment hours earlier.

Firefighters also improved containment of several smaller fires burning around the Panhandle, including one known as the Grape Vine Creek Fire, at 30,000 acres and 60% containment, and the Magenta Fire, at 2,500 acres and 65% containment.

The Forest Service said the colder weather was making the fires easier to fight, compared to conditions Monday and Tuesday. It said it was using bulldozers and motor graders to build dirt containment lines around the fires, focusing on protecting homes and other structures in the massive fires’ path.

The Smokehouse Creek Fire surpassed Texas’s largest wildfire on record, the East Amarillo Complex Fire. That fire killed a dozen people as it torched more than 907,000 acres in March 2006.

Texas wildfire records go back to 1988, and nearly all of the largest fires on the list have occurred since 2011. It’s probable that fires grew even larger hundreds of years ago, when humans didn’t take measures to suppress them and the land was less fragmented by development, said Michael Stambaugh, an associate professor of forest ecology at the University of Missouri.

Now, decades of fire suppression mean a greater buildup of vegetation that can burn. That includes more growth of trees, which burn hotter and can encourage fires to spread farther, said Victoria Donovan, an assistant professor of forest management at the University of Florida who has studied Great Plains fires.

But, more than anything, it just takes strong winds and abundant dry grasses to send wildfires spreading across areas the size of a football field within minutes, said Karl Flocke, a spokesman for the Forest Service at Texas A&M. Heavy rainfall across the Panhandle last summer allowed more grass to grow, providing extra fuel for this week’s fires, he said.

Fueling the Smokehouse Creek Fire were abnormal winter heat that set records across the Lone Star State, plus strong winds as a cold front approached in recent days. Temperatures surged into the 80s and 90s across the state early this week, including a high of 82 in Amarillo on Monday.

Forecasters said that if the fires aren’t contained or extinguished soon, they are expected to become much more difficult to fight by Saturday.

“Critical fire weather conditions are expected to develop across the area once again on Saturday and Sunday,” Weather Service forecasters wrote. Southwest winds are forecast to reach 30 mph, with stronger gusts, and relative humidity values could drop to 10 percent, they said, further drying out vegetation. Temperatures are forecast in the 70s.

The Forest Service on Wednesday raised a state wildland fire alert system to a level three on a five-step scale, signaling that wildfire activity is high and that assistance from multiple regions or states may be needed.

Activity to help care for people and livestock displaced by the fires was already beginning. In the city of Fritch, Texas, officials told residents an agency was en route to help shelter and feed livestock. In Borger, Texas, free food, clothing and household items were being gathered and provided at the Dome, an aluminum geodesic dome that serves as the city’s civic center.

Kasha Patel contributed to this report.