Northwest Fire District crews were battling two separate brush fires that quickly spread on the northwest side because of wind conditions until late Thursday night, officials said.
The district reported the fires in the Santa Cruz River near Silverbell Road and Sunset Dunes Place just before 6 p.m.
Firefighters continued to suppress the fires from spreading past the fire line set up by fire crews, said Capt. Brian Keeley, a district spokesman.
Only residents were being allowed to enter the area of Silverbell Road from Ina Road and Sunset Road for most of the evening. The frontage road of eastbound Interstate 10 at Orange Grove was closed for several hours.
Arizona Department of Forestry and Fire Management reported the Silverbell Fire burned more than 40 acres in the area around 7:15 p.m. Thursday.
Originally, a "very large" fire was reported by the fire district until further inspection led them to discover a second blaze.
Photos: Silverbell Fire
Silverbell Fire
Updated
Emergency personnel fight the Silverbell Fire at sunset just to the west of the I-10 and south of Orange Grove, Thursday, June 7, 2018, Tucson, Ariz.
Silverbell Fire
Updated
Eastbound traffic speeds by on I-10 as flames whip up from the Silverbell Fire just to the west of the highway and south of Orange Grove, Thursday, June 7, 2018, Tucson, Ariz. The eastbound frontage road is closed south of Orange Grove, Silverbell is closed between Sunset and Ina.
Silverbell Fire
Updated
One of the fingers of the Silverbell Fire finds some fuel and boils up near an utility pole to the west of the I-10 and south of Orange Grove, Thursday, June 7, 2018, Tucson, Ariz.
Silverbell Fire
Updated
The center blaze of the Silverbell Fire burns into a stretch of fuel near a fire truck to the west of the I-10 and south of Orange Grove, Thursday, June 7, 2018, Tucson, Ariz.
Silverbell Fire
Updated
The center finger of the Silverbell Fire burns into a pocket of fuel and flares up near run of utility lines just to the west of the I-10 and south of Orange Grove, Thursday, June 7, 2018, Tucson, Ariz.
Silverbell Fire
Updated
As the sun sets on the day, units try to get the jump on a hotspot of the Silverbell Fire just to the west of the interstate and south of Orange Grove, Thursday, June 7, 2018, Tucson, Ariz.
