BELLVUE, Colo. — Firefighters are making progress on a 93-square-mile wildfire in northern Colorado that has destroyed more homes than any other in state history, but more residents were warned Tuesday to be ready to leave because of a spot fire that ignited near the main fire.

The fire already has destroyed at least 189 homes since it was sparked by lightning June 9. Incident commander Bill Hahnenberg said it could be months before it’s finally controlled.

The wildfire is one of several in the West forcing people to flee, including another in Colorado that has driven out nuns at a monastery, Boy Scouts at camp and residents of 150 homes.

In California, firefighters were able to contain 75 percent of a 1,000-acre wildfire in mountainous eastern San Diego County despite gusty winds and low humidity levels.

In New Mexico, firefighters were taking advantage of favorable conditions to battle a Ruidoso wildfire that has destroyed 242 homes and businesses.

In Arizona, a 3,700-acre blaze on the Tonto National Forest was 15 percent contained .

In Nevada, a 10,000-acre wildfire north of Ely was 15 percent contained.