Three people have been reported missing after a large mudslide Sunday evening in Mesa County, Colo. 

The Mesa County Sheriff's Office said the slide occurred in a remote area near the town of Collbran, approximately 40 miles east of Grand Junction. KDVR-TV, citing police, reported that the slide occurred along Salt Creek Road in the area of Vega State Park. 

Authorities said the first report of the mudslide came at about 6:15 p.m. local time Sunday. The person who first reported the slide described hearing a sound like a freight train, according to a report by the Mesa County Sheriff's Office. No structures were reported damaged, nor were major roads reported to be impacted. 

A unified incident command has been established between Plateau Valley Fire Department and the Mesa sheriff, to handle the slide and search for the people possibly caught in it.

The mudslide is estimated to be 4 miles long, 2 miles wide, and 250 feet deep in most places. Rain had fallen in the area all day Sunday, and authorities believe it contributed to the slide. 

Rescue operations were halted as night fell due to the site's instability. Mesa County Sheriff's spokeswoman Lisa McCammon told the Associated Press that a daylight search was safer. 

In a statement, Lt. Phil Stratton of the Mesa County Sheriff's Office described the slide as "unbelievably big." A roadblock was established near Collbran and media and locals alike were "highly discouraged" from trying to access the site. 

 The avalanche occurred about two months after a massive mudslide hit the Washington state community of Oso on March 22, killing 43 people.

The Associated Press contributed to this report.