Ball Family article: https://www.newsobserver.com/news/sta...

USGS video:    • Debris flow experiment  effect of dr...  
Another:    • Insights from the USGS Debris Flow Fl...  

Helene caused a tremendous number of debris flow landslides. Often called mudslides, debris flows are literally rivers of liquefied mountainside containing boulders, soil, trees, and anything else in their way. This video uses maps and Microsoft Paint to illustrate how soil, when saturated and on a slope, can turn into a liquid and stay liquefied as long as it's moving. The example debris flow near Barnardsville, North Carolina, is well documented in the Ball Family newspaper articles and in Tim Burleson's Facebook videos. Debris flows seem like an impossible phenomenon, but are they really that rare in the Appalachians?