Debris Flow in Archuleta County, Colorado

At approximately 6:20 PM MDT, a severe thunderstorm moved southwest of Chimney Rock National Monument, producing heavy rain and hail. This heavy rain fell on an area of very steep terrain and produced a mud flow and small rock slide across Colorado Highway 151. Aside from the road needing to be cleared, no damage, injuries, or fatalities were reported in association with this debris flow.

A low pressure system had moved through eastern Utah and western Colorado in the days before this event, pumping anomalously rich moisture into southern portions of the region. While showers had lingered through the night into the morning of the 3rd, the clouds did not inhibit the development of instability through the morning hours. This instability ultimately led to the development of some strong to severe thunderstorms across southwest Colorado, producing some debris flows and severe hail.