Articles | Volume 26, issue 3
https://doi.org/10.5194/nhess-26-1537-2026
© Author(s) 2026. This work is distributed under the Creative Commons Attribution 4.0 License.
Tracking the slopes: a spatio-temporal prediction model for backcountry skiing activity in the Swiss Alps using user-generated content
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- Final revised paper (published on 25 Mar 2026)
- Supplement to the final revised paper
- Preprint (discussion started on 06 Jun 2025)
- Supplement to the preprint
Interactive discussion
Status: closed
Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor
| : Report abuse
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RC1: 'Comment on egusphere-2025-2344', Anonymous Referee #1, 13 Aug 2025
- AC1: 'Reply on RC1', Leonie Schäfer, 26 Sep 2025
- AC2: 'Reply on RC1', Leonie Schäfer, 26 Sep 2025
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RC2: 'Comment on egusphere-2025-2344', John Sykes, 21 Aug 2025
- AC3: 'Reply on RC2', Leonie Schäfer, 26 Sep 2025
Peer review completion
AR – Author's response | RR – Referee report | ED – Editor decision | EF – Editorial file upload
ED: Reconsider after major revisions (further review by editor and referees) (28 Oct 2025) by Pascal Haegeli
AR by Leonie Schäfer on behalf of the Authors (11 Dec 2025)
Author's response
Author's tracked changes
Manuscript
ED: Publish subject to technical corrections (16 Feb 2026) by Pascal Haegeli
AR by Leonie Schäfer on behalf of the Authors (19 Feb 2026)
Manuscript
This paper presents an analysis of backcountry skiing activity using GPS tracks and website click data. Machine learning is used to train predictive models and analyze feature importance. The resulting importances largely align with established literature. Deviations are in line with what can be expected from click data (i.e. planning data) and actual tracking data. The use of warning regions as analysis units makes sense even though I would have liked to see a sensitivity analysis with varying spatial resolution.
My main issue is that -- while temporal cross validation is applied -- a corresponding spatial cross-validation is missing.
Other issues in order of appearance include:
- 149 "Between 2013 and 2024, over 6’800 GPS tracks were uploaded by backcountry recreationists throughout all seasons except 150 for seasons 21/22 and 22/23." ... I assume this means that the last season included in the track dataset is 23/24. Can you include information on how many individual skiers contributed GPS tracks to the database? Is the number of users per year stable? What happened to the data from 21/22/23?
- 164 "Therefore, only data from 2021 onwards is included for modelling and prediction," ... so for prediction, we only have an overlap between click and track data in 20/21 and 23/24? (This seems to be confirmed by Table 2 & 3 but might be worth making explicit in the data section.)
- 209 "mean values were calculated based on the grid points that lie in an elevation band within ±100 m of the mean track elevation (track data), respectively the mean route elevation in a given region (click data)" ... Wouldn't it make sense to further limit the weather grid cells using a maximum distance to actual skiing routes?
- 272 "This approach resulted in four (nine) training runs, each cross-validated using four (nine) different seasons for the click (track) data." ... To make this sentence easier to for the reader, I suggest to reword it instead of putting the track model info in brackets.
- 348 "The underlying driver for the systematic overprediction of the track model lay in the modelling process itself, as artificially balanced 350 numbers of presence and absence points were used for training. When verified with real-life and therefore unbalanced data, the model predicted more presence than was observed." ... Please check if the use of past tense "lay" is appropriate or if present tense "lies" should be used since the model was not adjusted after the issue was discovered and all presented results are from the overpredicting model.
Minor issues:
- 386 "Figure 9 shows the importance for each variable for the performance of the model" ... Should probably be "importance of each variable".
- 387 "from each cross-validation seasons" ... Should probably be "season".