The discussers thank the authors for their effort in investigating the precursor to instability induced by internal erosion in loose, granular slopes (Hu et al., 2018a). In the discussed paper, the internal erosion was observed in flume experiments and the contribution of internal erosion to instability was investigated through undrained triaxial tests.
However, the internal stability of materials collected from the loose deposit of the rock avalanche in theWenjia gully and used forthe flume experiments requires further discussion.