Dear Dr. Theule,
I read your manuscript with interest and agree with both referees it should be published in NHESS, provided some minor revisions as indicated in the referee reports are applied. To proceed with the closed peer-review process, please resubmit your revised manuscript accompanied by a version in track change mode highlighting the applied changes and your detailed point-per-point reply to the referee comments as published in the interactive discussion. After resubmission, your article will be reviewed again by the editor.
Best regards, A. Günther

Dear Dr. Theule,

I am pleased to inform you your revised paper can now be accepted for publication in NHESS. When reading your article, I made some editorial observations outlined below that you may consider before final resubmission of your manuscript.

Best regards, A. Günther

P2, L55: “GoPro recording”: What is this? Maybe explain.
P5, L105: “LSPIV calculation on the freeware…”: Maybe rephrase to “the LSPIV calculations were performed using the freeware…”
P5, L108: “resolution 1689x1345”: in DPI?
P5, L117: “this used to be necessary for the Fudaa software”: Unclear.
P6, L133: Maybe rephrase section heading to “LSPIV calculations using Fudaa” or similar.
P6, L143: Flow velocity not shown in Fig. 2C. Please give reference to this Figure when describing IA.
P6, L145: “search area”: Please give reference to SA in Fig. 2C.
P9, L180: “four surges”: It would be good to denote S1 to S4 in brackets here.
P9, L186: “because of the surges variable rheology”: maybe rephrase to “because of the variable rheology of the surges”.
P12, L219: “feature picking that does not always represent…”
P14, L236: “17:23:10”: please indicate once that these are time steps.
P19, L287: “strong correlation with” or “strong relation to”.

Figure 1: This may be rearranged to fit a rectangle. Position of the study site in A should be enlarged or/and labelled in the Figure.
Figure 2: All images have no orientations and scales. IA and SA in C should be plotted with thicker lines, the reference to the colors in the legend should be deleted.
Figure 3: Images have no orientations and scales. Even though these can be estimated when looking at Fig. 1, it may be convenient to indicate at least the orientations of the cameras in this Figure.
Figure 6: Images have no scales.
Figure 8: B has no scale. In A, please reconsider the y-axes labelling (“m/m”, “depth”). In the caption, it reads “along the long profile of the grid in Fig. 7”. Please specify what is meant here.
Figure 9: Please denote A to D and explain the four graphs in the caption separately.