Slumgullion Earthflow

Slumgullion Earthflow is a landslide formation in the San Juan Mountains that stretches several miles and is marked by yellow soil and tilted trees. The surface shows clear signs of ground movement that has created this distinctive landscape feature over an extended period.

The initial landslide occurred about 700 years ago when volcanic rock from Mesa Seco collapsed and formed a natural dam. This event led to the creation of Lake San Cristobal and shaped the geological history of the area.

The name comes from early settlers who likened the yellow soil to a common miners' stew from the 1800s. This naming reflects the everyday language of prospectors who traveled through the region.

Visitors can observe the formation from designated viewpoints along Highway 149, with Windy Point Overlook providing the clearest views. Visiting multiple overlooks helps you understand the full extent of the formation.

A second earthflow that began roughly 300 years ago remains geologically active and shows continuous movement. This ongoing activity makes the site valuable for geological research and understanding slope instability.

Location: Colorado

GPS coordinates: 37.99170,-107.25700

Latest update: December 8, 2025 19:49