Due to heavy and continuous rainfall the surface water percolated into the cracks of the overburden. This resulted into saturation and increase of pore pressure causing failure.

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_MDR_ 060
Chainage 49km, (0 km at Pokhri)
Improvement of drainage network, sealing of cracks, breast wall with lined toe drain, controlled irrigation, retaining wall along the affected length of road.
Heavy rainfall caused saturation and reduction in shear strength of the overburden.