Rapid growth on the South Rim fire in Black Canyon of the Gunnison National Park forced immediate evacuations in Montrose County on Saturday afternoon.

Firefighters are trying to contain several more fires on the Western Slope, and air quality alerts are in effect for much of the state.

As of Thursday at 1:20 p.m., crews were battling wildfires on both rims of Black Canyon of the Gunnison in Montrose County, according to the Colorado Division of Fire Prevention and Control.

Four wildfires are burning on thousands of acres in western Colorado, prompting a slew of mandatory evacuations, and a fifth fire is approaching from Utah, federal officials said in Sunday morning

The Deer Creek and South Rim fires are burning in Montrose County, with the South Rim Fire estimated at 3,500 acres as of Sunday morning. Black Canyon of the Gunnison National Park in southwestern Colorado is closed due to wildfires on both rims of the canyon.