'Unbelievably Big' Mudslide Leaves 3 Missing Rain believed to have contributed to Colorado slide By Kevin Spak, Newser Staff Posted May 26, 2014 6:30 AM CDT 7 comments Comments Colorado authorities are searching for three people missing after a massive mudslide in Mesa County. (ExpressNewsChannel) (Newser) – Three people are missing in the wake of a massive mudslide that struck near Collbran, Colorado, last night. The slide was reported at around 6:15pm, after a day of rain that is believed to have helped cause the slide, the Denver Post reports. The caller "described hearing a noise that sounded much like a freight train," the sheriff's department said. The slide is an estimated 4 miles long, 2 miles wide, and 250 feet deep. "This slide is unbelievably big," one police officer said. The area is still considered unstable, and roadblocks have been set up to try to keep people away from it, the Denver Channel reports. Rescue crews are combing the area for anyone who may have been trapped in the slide. So far no structures have been reported as damaged, and no major roads have been affected. The area is so remote that it does not get cellphone service.