DENVER (CBS4)– A prescribed burn at the former Rocky Mountain Arsenal sent up plumes of smoke over the Denver metro area on Wednesday.

The prescribed burn happened at the Rocky Mountain National Wildlife Refuge. About 400 acres were burned.

Rocky Mountain Wildlife Refuge (credit: CBS)

Rocky Mountain Wildlife Refuge (credit: CBS)

A similar burn occurred on Friday. The prescribed burns are designed to reduce fuels and improve wildlife habitat.

(credit: CBS)

(credit: CBS)

According to the Rocky Mountain Arsenal National Wildlife Refuge website, it is located 10 minutes from downtown Denver. It’s nearly 17,000 acres, making it one of the largest urban wildlife refuges in the United States. It consists of open lakes, wetlands, prairie grasslands, and woodlands.

WEB EXTRA VIDEO: See an interview with Rocky Mountain National Wildlife Refuge spokeswoman Cindy Souders about controlled burns