Heavy rainfall caused saturation of the debris material which resulted in loss of cohesion and inter friction angle of overburden mass and eventually started moving down.

An Interim Report on Preliminary  Geological  Slope Stability Assessment of the Recent Disaster Affected Areas in Parts of Chamoli District, Uttarakhand by Bhupendra Singh, Bhupender Singh, Ajay Kumar and Arindam Roy, Senior Geologists, M-IV, NR GSI Dehr
UK_CHA_NH_ 039
Along NH-87E near Ujalpur village after Adibadri
Benches on the slope, diversion of surface run off, improvement of drainage network, geomembrane/geojuting with mulching of suitable plants.
Heavy rainfall in the area for 3-4 days caused saturation and reduction in strength of slope material which made way for downslope mobilization of the slope material.