WESTCLIFFE, Colo. — A wind-driven wildfire in southern Colorado destroyed one structure Monday and forced residents to flee 130 homes, authorities said.

The fire was reported about 3:30 a.m. Monday some 25 miles west-southwest of Pueblo, the Custer County Emergency Management Office said.

It had grown to 21 square miles by Monday evening, said El Paso County sheriff’s spokeswoman Gail Perez. High wind gusts grounded water-dropping aircraft, she said. The cause was unknown.

At least one structure was destroyed, Perez said.

People in the small town of Beulah, which was evacuated by another wildfire earlier this month, were told to be ready to leave.

Firefighters from throughout the state headed to the blaze to assist crews from Custer and Pueblo counties. About 80 personnel were on the scene, and three air tankers were deployed.

The fire sent up large plumes of smoke, which led to a health advisory for people living as far east as Pueblo.

A stretch of dry, warm weather has raised the fire danger in much of Colorado, especially on windy days.

The fire that evacuated Beulah is believed to have been started by a state-operated excavator working in a ditch, possibly by creating a spark.

To the north, firefighters contained more than 50 percent of a 14-acre wildfire in Pike National Forest about 10 miles northwest of Colorado Springs. No structures were damaged.

Oscar Martinez, a district ranger with the U.S. Forest Service, said he hoped crews could fully contain the fire on Tuesday.

The fire was reported Monday afternoon near Rampart Reservoir. Its cause was unknown.