The slumgolian slide is composed of a loosely welded sulfur rich volcanic tuff. It is very porous, and has the ability to absorb a large amount of moisture. This photo was taken in March of 2004, it was a very warm March day (57deg F) and the winter snowfall was in full melt. The loosely welded tuff was gaining weight from the melting snow water, and at the same time is was loosing its consistency by becoming muddy, thus reducing fiction in and between its beds.

Over time, the gradually flowing lower mudslide caries material away from the cliff face, increasing the angle of the slope below the cliff face. Periodically, the cliff face fails due to the undercutting of the lower slide beneath it. This causes a mass run on landslide, capable of traveling several miles or more. The wet muddy lower landslide serves as bal bearings, by reducing the friction in travel for the upper cliff face material. Rocks slide well down steep muddy slopes.

Two mass run on landslides, one 1200 years ago, and one 800 years ago, flowed south over 3 miles down into valley floor. There, they damned the lake fork of the Gunnison River to form Lake San Cristabol. Today, Lake San Cristobal is one of the largest and most scenic natural lakes in Colorado. A community of cabins has been established along the north side of the lake. Many of these cabins are built on ancient landslide deposits. The one thing that is likely to save many the cabins residence, is that the cabins are likely to be empty when the landslide occurs. Spring melt season is not a popular time time to reside in a cabin on Lake San Cristabol.