Thornton Fire LIVE: Grass Fire Forces Evacuations, Shuts Down I-25 Near Denver
⚠️ DEVELOPING STORY — February 25, 2026
A fast-moving grass fire erupted Wednesday morning in Thornton, Colorado, sending a massive plume of thick black smoke over the north Denver metro area and triggering emergency evacuations of a high school, businesses, and residential neighborhoods. The Thornton fire is one of the most significant fire emergencies in the Denver region since the 2022 Marshall Fire.
Thornton Fire: What Is Happening Right Now
The Thornton Police Department confirmed the grass fire broke out between approximately 11:00 AM and 12:00 PM ET in the grassy area north of Pinnacle High School, near 84th Avenue and Huron Street. The fire spread rapidly, overwhelming roads and visibility across the entire northern Denver corridor within minutes of ignition.
Thornton Fire crews, along with several neighboring departments, responded to the scene at Pinnacle High School, classifying the blaze as a vegetation fire. Interstate 25 was closed in both northbound and southbound directions at 84th Avenue.
I-25 Shut Down in Both Directions
Both directions of I-25 were closed between U.S. Route 36 and 104th Avenue due to safety concerns, according to the Colorado Department of Transportation. Black smoke billowed across the CDOT camera at I-25 and Thornton Parkway.
Traffic cameras captured black smoke billowing across the highways, recalling earlier images from the 2022 Marshall Fire. Drivers were urged to avoid the area entirely to allow emergency vehicles to respond freely and to prevent exposure to heavy smoke.
Pinnacle High School and Neighborhoods Evacuated
Pinnacle High School and nearby businesses were evacuated. Police also began door-to-door evacuations in neighborhoods to the northeast. A school spokesperson confirmed Pinnacle High School was placed on a controlled release, with families instructed to pick up their children at Pinnacle Event Center.
Residents who live in the area and cannot go home are being asked to go to Water World as a safe location and not return home until authorities provide clearance.
Dangerous Fire Weather Conditions Fueling the Thornton Fire
CBS Colorado First Alert meteorologists had called a First Alert Weather Day on Wednesday due to high winds, unseasonably warm and dry conditions, and high fire danger. A red flag warning was in effect for the second consecutive day for areas below 6,000 feet, running from the Front Range foothills into the Eastern Plains, including the Denver metro area, from 10:00 AM through 6:00 PM ET.
Wind gusts were expected to reach as high as 55 mph, with high temperatures in the 60s to low 70s and relative humidity dropping to around 10%. Those conditions increase the speed at which grass fires spread and complicate suppression efforts.
What Residents Should Know Right Now
Police said that while emergency personnel were conducting manual evacuations, anyone who does not feel safe should evacuate immediately without waiting for door-to-door contact. Anyone displaced by the Thornton fire is directed to Water World as the designated community shelter. All road closures remain active and no return timeline has been announced.
This is a developing story. Conditions are changing rapidly.
