debris flow

USGS

The area where the Collbran mudslide happened has seen similar slides in the past. Geologists say relatively weak rock and steep terrain create a recipe for such natural disasters. Still, Colorado in general is less vulnerable to slides than wetter areas, like the west coast. Aspen Public Radio's Marci Krivonen reports.

The Colorado Geological Survey began mapping landslides near Collbran in the 1980’s. They discovered the area where this debris flow happened was prone to slides.