Arizona residents near Patagonia in Santa Cruz County were put on an evacuation alert as a 1,200-acre wildfire drew near, according to the Santa Cruz County sheriff's office.
The new fire, called the Red Rock fire, started Thursday afternoon about five miles east of Patagonia.
State fire officials said the fire could get worse before fire crews will be able to bring it under control.
Forest Service reports indicated there was a potential for structures to be damaged as the fire burned south and east in grasslands with brush and scattered oak trees.
Though the weather was expected to be hot and dry through the weekend, winds were forecast to stay light.
By Friday afternoon the American Red Cross had set up a shelter for evacuees at the Santa Cruz County Fairgrounds in Sonoita.
Patagonia, 50 miles southeast of Tucson, is home to about 900 people. The fire was presumed to be human-caused since no lightning storms were recently in the area.
For many fire responders, the Red Rock fire – named for the canyon in which it began – marks the beginning of fire season.
The Red Rock blaze is the fourth "large fire" – defined as greater than 100 acres – to hit southern Arizona in 2003.
Last year the Rodeo-Chediski fire, near Show Low, burned some 460,000 acres. Another large fire last year in Ryan – near Sonoita – burned some 38,000 acres.
During the 2002 Arizona fire season, there were 1,833 human-caused fires, and 1,385 caused by lightning.
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