Slumgullion Earthflow

The Slumgullion Earthflow is a remnant of a landslide in the San Juan Mountains in Hinsdale County, Colorado. It was designated a National Natural Landmark in 1983. It is also a Colorado Natural Area and an Area of Critical Environmental Concern.^[1][2][3]

The earthflow, a slow-moving landslide, crawled down the valley about 700 years ago creating the 4 miles (6.4 km) long and 2,000 feet (610 m) wide mass.^[1][2] The earthflow lies a few miles southeast of Lake City.^[2] The landmark site covers 1,291 acres (522 ha) and is owned and managed by the US Forest Service and the Bureau of Land Management. 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.^[1] A second earthflow has been moving continuously for about 300 years over older stable rock.^[3] It moves at a rate of about 7 meters (23 feet) per year.^[4]

The area is a habitat for elk and deer.^[2] It is crossed by Colorado Highway 149, the principal highway of the area connecting Lake City with Creede.

References

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 Protected areas of Colorado

Federal

4 National Parks	Black Canyon of the Gunnison Great Sand Dunes Mesa Verde Rocky Mountain
9 National Monuments	Browns Canyon (BLM-USFS) Camp Hale-Continental Divide (USFS) Canyons of the Ancients (BLM) Chimney Rock (USFS) Colorado Dinosaur Florissant Fossil Beds Hovenweep Yucca House
3 National Historic Sites	Amache Bent's Old Fort Sand Creek Massacre
2 National Recreation Areas	Arapaho (USFS) Curecanti
1 Wild and Scenic River	Cache la Poudre River
4 National Historic Trails	California Trail Old Spanish Trail Pony Express Trail Santa Fe Trail
1 National Scenic Trail	Continental Divide Trail
11 National Forests	Arapaho Grand Mesa Gunnison Medicine Bow–Routt Pike Rio Grande Roosevelt San Isabel San Juan Uncompahgre White River
2 National Grasslands	Comanche Pawnee
44 National Wildernesses	Black Canyon of the Gunnison Black Ridge Canyons Buffalo Peaks Byers Peak Cache La Poudre Collegiate Peaks Comanche Peak Dominguez Canyon Eagles Nest Flat Tops Fossil Ridge Great Sand Dunes Greenhorn Mountain Gunnison Gorge Hermosa Creek Holy Cross Hunter–Fryingpan Indian Peaks James Peak La Garita Lizard Head Lost Creek Maroon Bells-Snowmass Mesa Verde Mount Evans Mount Massive Mount Sneffels Mount Zirkel Neota Never Summer Platte River Powderhorn Ptarmigan Peak Raggeds Rawah Rocky Mountain National Park Sangre de Cristo Sarvis Creek South San Juan Spanish Peaks Uncompahgre Vasquez Peak Weminuche West Elk
3 National Conservation Areas	Dominguez–Escalante Gunnison Gorge McInnis Canyons
8 National Wildlife Refuges	Alamosa Arapaho Baca Browns Park Monte Vista Rocky Flats Rocky Mountain Arsenal Two Ponds
3 National Heritage Areas	Cache la Poudre River Corridor Sangre de Cristo South Park
28 National Historic Landmarks	Beaver Meadows Visitor Center Bent's Old Fort Central City/Black Hawk Historic District Colorado Chautauqua Cripple Creek Historic District Cumbres and Toltec Scenic Railroad Denver Civic Center Durango and Silverton Narrow Gauge Railroad Elitch Gardens Carousel Georgetown–Silver Plume Historic District Granada War Relocation Center Leadville Historic District Lindenmeier site Lowry Pueblo Ludlow Tent Colony Site Mesa Verde Administrative District Minnequa Steel Works Pikes Peak Pike's Stockade Raton Pass Red Rocks Park Shenandoah-Dives Mill Silverton Historic District Telluride Historic District Temple Aaron Trujillo Homesteads United States Air Force Academy, Cadet Area Winks Panorama
16 National Natural Landmarks	Big Spring Creek Garden of the Gods Garden Park Fossil Area Hanging Lake Indian Springs Trace Fossil Natural Area Lost Creek Scenic Area Morrison-Golden Fossil Areas Raton Mesa Roxborough Russell Lakes Sand Creek Slumgullion Earthflow Spanish Peaks Sulphur Cave and Spring Summit Lake West Bijou Site
National Register of Historic Places	National Register of Historic Places listings in Colorado

State

43 State Parks	Arkansas Headwaters Barr Lake Boyd Lake Castlewood Canyon Chatfield Cherry Creek Cheyenne Mountain Crawford Eldorado Canyon Eleven Mile Elkhead Fishers Peak Golden Gate Canyon Harvey Gap Highline Lake Jackson Lake James M. Robb - Colorado River John Martin Reservoir Lake Pueblo Lathrop Lone Mesa Lory Mancos Mueller Navajo North Sterling Paonia Pearl Lake Ridgway Rifle Falls Rifle Gap Roxborough Spinney Mountain St. Vrain Stagecoach State Forest Staunton Steamboat Lake Sweetwater Lake Sweitzer Lake Sylvan Lake Trinidad Lake Vega Yampa River
1 State Forest	State Forest
307 State Wildlife Areas	List of Colorado state wildlife areas
96 State Natural Areas	Aiken Canyon Antero-Salt Creek Arikaree River Badger Wash Blacks Gulch Blue Mountain-Little Thompson Fault Bonny Prairie Boulder Mountain Park Brush Creek Fen California Park Castlewood Canyon Chalk Bluffs Coal Creek Tallgrass Prairie Colorado Tallgrass Prairie Comanche Grassland Copeland Willow Carr Corral Bluffs Cross Mountain Canyon Dakota Hogback Deer Gulch Dome Rock Droney Gulch Duck Creek Dudley Bluffs East Lost Park East Sand Dunes Elephant Rocks Escalante Canyon Fairview Fourmile Creek Fruita Paleontological Garden Park Fossil Gateway Palisade Geneva Basin Iron Fens Gothic Gunnison Gravels Haviland Lake High Creek Fen High Mesa Grassland Hoosier Ridge Hurricane Canyon Indian Spring Indian Springs Trace Fossil Irish Canyon Jimmy Creek Ken-Caryl Ranch Kremmling Cretaceous Ammonite Limestone Ridge Lookout Mountain Lower Greasewood Creek McElmo Mexican Cut Mini-Wheeler Miramonte Reservoir Mishak Lakes Mount Callahan & Logan Wash Mine Mount Emmons Iron Bog Mount Goliath Narraguinnep Needle Rock North Park Phacelia Orient Mine Owl Canyon Pagosa Skyrocket Paradise Park Park Creek Hogback Pyramid Rock Rabbit Valley Rajadero Canyon Raven Ridge Redcloud Peak Rough Canyon Roxborough Ryan Gulch Saddle Mountain San Miguel River Sand Creek Shell Duck Creek Shell Rock Slumgullion Earthflow South Beaver Creek South Boulder Creek South Cathedral Bluffs Specimen Mountain Staunton Tamarack Ranch Treasurevault Mountain Trinidad K-T Boundary Two Buttes Unaweep Seep Wacker Ranch West Creek Wheeler Geologic White Rocks Yanks Gulch/Upper Greasewood Creek Natural Area Zapata Falls
26 Scenic and Historic Byways	Alpine Loop Cache la Poudre-North Park Collegiate Peaks Colorado River Headwaters Dinosaur Diamond Flat Tops Trail Frontier Pathways Gold Belt Tour Grand Mesa Guanella Pass Highway of Legends Lariat Loop Los Caminos Antiguos Mount Evans Pawnee Pioneer Trails Peak to Peak San Juan Skyway Santa Fe Trail Silver Thread South Platte River Trail Top of the Rockies Tracks Across Borders Trail of the Ancients Trail Ridge Road/Beaver Meadow Unaweep Tabeguache West Elk Loop

Trails

28 National Recreation Trails	Apex Barr Bear Creek Big Dry Creek Calico Crag Crest Devils Head Fish Creek Falls Grays Peak Greyrock Mountain High Line Canal Highline Loop Lake Fork Mineral Belt Mount Evans Mount McConnel Petroglyph Point Platte River Greenway Poudre River Rocky Mountain Arsenal Round Mountain Swamp Park Two Elk Two Ponds Vail Pass West Lost Trail Creek Wheeler Ten Mile White House Ranch
6 Regional Trails	American Discovery Trail Colorado Trail Great Divide Mountain Bike Route Kokopelli's Trail Paradox Trail Tabeguache Trail

• Colorado Department of Natural Resources