Fueled by red flag winds, the blaze in Thornton blackened 10 acres, shut down I-25 and sent between 100 and 150 firefighters scrambling door to door to clear homes

By Lauren Penington, Katie Langford
The Denver Post

THORNTON, Colo. — Thornton police officers went door-to-door Wednesday afternoon to evacuate residents after a grass fire sparked near a high school, rapidly spreading and injuring five people, according to law enforcement.

The fire burned for more than two hours in Thornton before the city’s fire department announced the flames had been fully contained at 2:07 p.m. Wednesday. At that time, the fire had consumed roughly 10 acres, Thornton Fire Chief Stephen Kelley said in a news conference. Residents were allowed to return home shortly after 3:30 p.m. Wednesday, Thornton Police Department said in an update.

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Fire crews from across the Denver area responded to the fire at about 11:30 a.m. Wednesday, Kelley said. By noon, heavy, black smoke blowing from the scene had shut down Interstate 25.

The fire chief estimated that between 100 and 150 firefighters from various agencies responded to the fire.

No homes were destroyed in the fire, which started on a greenbelt between a residential neighborhood and local businesses, Kelley said. The cause of the fire remained under investigation on Wednesday and damage to the businesses was still being evaluated, he said.

“It is our intent to get ahead of these fires so we don’t have the spread … experienced during the Marshall fire,” Kelley said. “I think we’re very fortunate today that we did not have an outcome similar.”

No fatalities or critical injuries from the fire were reported on Wednesday, Kelley said. Five people, including four firefighters, were injured in the fire but are expected to survive. Additional information on their injuries was not available.

High winds fueled the fire’s “rapid spread” as most of the Front Range and Eastern Plains remained under a red flag warning, Kelley said.

The warning, which will be in effect until 6 p.m. Wednesday , covers parts of Larimer , Weld , Boulder , Jefferson , Broomfield , Douglas , Denver , Adams , Arapahoe , Morgan , Elbert , Lincoln , Logan , Washington , Sedgwick and Phillips counties, according to the National Weather Service .

Up to 55 mph wind gusts and humidity values as low as 15% are forecast through Wednesday evening, forecasters said in the warning.

“These are conditions that we continue to face on a daily basis here on the Front Range,” Kelley said.

Interstate 25 was closed in both directions for more than an hour near the fire’s start for low visibility, a closure that steadily grew before it was fully lifted at 1:30 p.m. Wednesday. During the closure’s peak, all lanes of I-25 were closed between Colorado 53/ 58th Avenue in North Washington and 104th Avenue in Thornton, according to the Colorado Department of Transportation.

Cameras along I-25 in the area of the fire showed thick, black smoke drifting across the highway just after noon on Wednesday.

Pinnacle Charter High School and nearby businesses were evacuated and several roads around the fire — which sparked near the high school at West 84th Avenue and Huron Street — were closed, according to the Thornton Police Department.

Continued road closures are expected in the area as fire crews work to extinguish hotspots and ensure the flames don’t rekindle amid high winds, Kelley said. Crews will remain in the area overnight.

The exact evacuation area is unknown, but police said it covered neighborhoods northeast of the fire. Information on the number of people and homes in the evacuation zone was not available.

Police established a formal evacuation shelter at the Margaret Carpenter Recreation Center, 11151 Colorado Blvd., after residents were initially directed to Water World.

Thousands of Xcel Energy customers remained without power in the area Wednesday afternoon, according to the utility’s outage map.

Outages included more than 3,000 customers in Jefferson County near Arvada and Westminster, 200 customers in Adams County near Sherrelwood and dozens of small outages in between, according to the utility.

Xcel Energy did not proactively de-energize power lines in the area, but utility officials were working with fire crews and were ready to shut down lines if needed, spokesperson Michelle Aguayo said.

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