Landslide, Mud/Debris Flow, and Rockfall in Colorado

Land movement related to landslides, mud and debris flows, and rockfalls occurs naturally across Colorado on a continuous basis, and can also be triggered through human activity (primarily related to mining, land development, and other disturbances). These events can occur at any time of the year from almost any location along a slope; however, because they are correlated with elevation change, these hazards largely occur in the mountainous region from the Front Range to the West Slope.

According to READY Colorado, it is estimated that there are thousands of landslides in Colorado each year, with varying degrees of frequency and severity. Most of these events do not result in casualties or property damage, though the annual damage in Colorado is estimated to exceed $3 million to buildings alone (Colorado Natural Hazards Mitigation Plan, 2013, p. 3-185). A massive landslide in a relatively unpopulated area of Mesa County near Grand Junction killed three people in 2014, leaving a swath of debris three miles long and ¾ of a mile wide. A deadly rockfall in September 2013 claimed five lives of a vacationing family following heavy rains near a popular hiking location near Buena Vista, Colorado (Shoichet, et al., 2013). Rockfalls are less frequent but remain a constant threat, particularly to Colorado’s mountain roadways. All of these geologic hazards may endanger Colorado’s built environment and can damage or destroy buildings, roads, and other infrastructure when proper land use or mitigation practices are not considered.