Colorado fires burn thousands of acres, kill 3 firefighters

(CNN) - Three firefighters, including a pilot spreading fire retardant, have died in southeastern Colorado wildfires sweeping across nearly 20,000 drought-stricken acres over two days, authorities said Wednesday.

The causes of the three fires - all of which began Tuesday - were unknown, and were being investigated.

Two of the men killed were volunteers with the Olney Springs Fire Department who were fighting a fire at Ordway that covered 8,900 acres, or about 14 square miles, said spokesman Chris Sorensen. Ordway is east of Pueblo. That fire was 90 percent contained, he said.

A spokeswoman at Fort Carson - an Army base where a second fire had burned 9,600 acres by Wednesday afternoon - said the third death was a pilot dropping fire retardant. Fort Carson is south of Colorado Springs, and about 50 miles northwest of Ordway.