Due to unprecedented rainfall and cloud burst in the Alaknanda valley, flash flood occurred in the river and it eroded the toe of the old debris cone. Already saturated debris material with diminishing shear strength failed because of this.  

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_ 009
About 100 m downstream of Ghat village.
Concrete retaining wall, slope dressing, breast wall with lined toe drain, training of spring water from debris.
Heavy precipitation, toe cutting by Alakananda River, continuous percolation of water from flowing nala, saturation of overburden mass leading to reduction in shear strength.