The Willacy County Sheriff's Office and other local fire departments are responding to a large structure fire Thursday afternoon. 

Drivers are asked to avoid the area of FM 2099 and FM 3142 until further notice. 

A Red Flag Warning remains in effect for all four Valley counties until 8 p.m. 

A Red Flag Warning means warm temperatures, very low humidities, and stronger winds are expected to combine to produce an increased risk of fire danger, according to the National Weather Service. 

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