The Smokehouse Creek Fire in Texas, which has merged with another fire and crossed the state line into western Oklahoma, was only 15 percent contained after five days, according to the Texas A&M Forest Service.
Strong winds and dry conditions on Saturday threatened to intensify the monster wildfire which is already the largest in state history.
The fire has burned more than 1.1 million acres across the Texas Panhandle and destroyed 500 structures, Texas authorities confirmed.
The National Weather Service in Amarillo has issued a red flag warning for the entire Panhandle from late Saturday morning through midnight Sunday after rain and snow on Thursday allowed firefighters to contain a portion of the fire.
The fires have killed at least two people.
Joyce Blankenship, 83, was found dead in her destroyed Hutchinson County home, officials said.
On Thursday it was confirmed that a second woman – Cindy Owens – had succumbed to her injuries after getting out of her truck and being severely burned.