The Slumgullion Earthflow in the

San Juan Mountains The San Juan Mountains is a high and rugged mountain range in the Rocky Mountains in southwestern Colorado and northwestern New Mexico. The area is highly mineralized (the Colorado Mineral Belt) and figured in the gold and silver mining industry ...

in Hinsdale County,

Colorado Colorado (, other variants) is a state in the Mountain West subregion of the Western United States. It encompasses most of the Southern Rocky Mountains, as well as the northeastern portion of the Colorado Plateau and the western edge of t ...

has been a

National Natural Landmark The National Natural Landmarks (NNL) Program recognizes and encourages the conservation of outstanding examples of the natural history of the United States. It is the only national natural areas program that identifies and recognizes the best ...

since 1983. It is also a

Colorado Natural Area The U.S. State of Colorado has designated 95 natural areas of the state for special protection. The Colorado Natural Areas Program was established in 1977 to preserve and protect special areas of the state with distinctive flora, fauna, ecologica ...

and an

Area of Critical Environmental Concern Areas of Critical Environmental Concern (ACEC) is a conservation ecology program in the Western United States, managed by the Bureau of Land Management (BLM). The ACEC program was conceived in the 1976 Federal Lands Policy and Management Act (FL ...

. The

earthflow An earthflow (earth flow) is a downslope viscous flow of fine-grained materials that have been saturated with water and moves under the pull of gravity. It is an intermediate type of mass wasting that is between downhill creep and mudflow. The ty ...

, a slow-moving landslide, crawled down the valley about 700 years ago creating the long and wide mass. The earthflow lies a few miles south east of Lake City. The landmark site covers and is owned by the

US Forest Service The United States Forest Service (USFS) is an agency of the U.S. Department of Agriculture that administers the nation's 154 national forests and 20 national grasslands. The Forest Service manages of land. Major divisions of the agency inc ...

and the

Bureau of Land Management The Bureau of Land Management (BLM) is an agency within the United States Department of the Interior responsible for administering federal lands. Headquartered in Washington DC, and with oversight over , it governs one eighth of the country's la ...

. It is "a striking example of mass wasting (the movement of large masses of earth material)." The Lake Fork of the Gunnison River was dammed by the earthflow, creating Lake San Cristobal. A second earthflow has been moving continuously for about 300 years over older stable rock. It moves at a rate of about 7 meters (23 feet) per year. The area is a habitat for elk and deer. It is crossed by

Colorado Highway 149 State Highway 149 (SH 149) is a state highway in southwestern Colorado, United States. SH 149's southern terminus is at U.S. Highway 160 (US 160) in South Fork, and the northern terminus is at US 50 west of Gunnison. The ...

, the principal highway of the area connecting

Lake City, Colorado Lake City is a List of municipalities in Colorado#Statutory town, Statutory Town that is the county seat, the most populous community, and the only List of municipalities in Colorado, incorporated municipality in Hinsdale County, Colorado, Hinsda ...

with Creede.

References

{{authority control Landforms of Hinsdale County, Colorado San Juan Mountains (Colorado) National Natural Landmarks in Colorado Protected areas of Hinsdale County, Colorado Geology of Colorado