Thornton Fire Sends Thick Black Smoke Over Denver Metro; I-25 Shutdown, School and Business Evacuations

A grass blaze north of Denver forced door-to-door evacuations and multiple road closures after thick, black smoke was seen billowing across the area. The thornton fire prompted officials to close sections of Interstate 25 and evacuate a high school and nearby businesses while strong winds and dry conditions raised immediate concern.

Thornton Fire: Evacuations, road closures and local impacts

Police officers were conducting door-to-door evacuations in neighborhoods northeast of the fire. Residents in the affected area were directed to relocate to Water World and not to return home until cleared. Pinnacle High School and adjacent businesses at 84th Avenue and Huron were evacuated as the grass fire moved through the vicinity.

Both directions of I-25 were closed between U. S. 36 and 104th Avenue for safety reasons, and traffic cameras in the area captured thick smoke drifting across the highway and billowing over the northern part of the Denver metro. At one point the left lane of southbound I-25 in the same corridor was closed and later reopened.

Officials urged drivers to avoid the area to allow emergency vehicles to respond and to reduce exposure to smoke. The precise boundaries of the evacuation zone were described as covering neighborhoods northeast of the fire.

Closures and guidance: what was affected

• Interstate 25: both directions closed between U. S. 36 and 104th Avenue for safety concerns.
• Pinnacle High School: evacuated along with nearby businesses at 84th Avenue and Huron.
• Neighborhoods northeast of the fire: door-to-door evacuations were underway.
• Designated relocation point: residents unable to return home were directed to Water World.

Weather, winds and fire danger that fueled the blaze

Forecasters called a First Alert Weather Day because of high winds, unseasonably warm and dry conditions that elevated fire danger. A red flag warning was in effect for the second day in a row for areas below 6, 000 feet from the Front Range foothills into the Eastern Plains, and it covered the Denver metro area over a midday to afternoon period.

Winds were expected to gust 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, contributing to the rapid escalation that produced the visible smoke plume over I-25 and surrounding neighborhoods.

Near-term outlook and safety reminders

Emergency responders remained on scene with road and school closures in effect while suppression and containment efforts continued. Residents in evacuated neighborhoods were advised not to return until authorities lift restrictions. Drivers were asked to steer clear of the area to keep routes clear for emergency vehicles and to limit exposure to heavy smoke.

This remains a developing situation and details may evolve as response operations continue.