the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
| 05 Jun 2026
Method for near real-time detection of snow avalanches using Distributed Acoustic Sensing
Abstract. We present a novel method for near real-time snow avalanche detection using Distributed Acoustic Sensing (DAS). A ∼10 km long telecommunication cable permanently installed along the avalanche-prone Flüelapass road (Swiss Alps) was continuously monitored over a full winter. Avalanches, including events that did not physically reach the cable, were clearly recorded and confirmed with photographic evidence. To discriminate avalanches from anthropogenic signals, we introduce a dual-frequency short-term over long-term average attribute that produces coherent high-value spatio-temporal signatures for avalanches, while vehicles predominantly generate negative values with pronounced move-out. The workflow consists of (1) a quasi-instantaneous threshold-based trigger to detect onset time and location, followed by (2) a rapid waterfall image analysis to estimate event extent and invalidate traffic-induced alerts. The first step issues alerts with millisecond-scale latency and meter-scale spatial resolution. The second step introduces additional latency, as it requires the event to sufficiently develop in order to assess its spatio-temporal morphology and confirm or discard the initial trigger. Our system issued alerts only 4.5 ‰ of the time when the road pass was open (i.e. 2.5 hours over 23 days), demonstrating the robustness against traffic, and 0.36 ‰ of the time when the pass was closed (i.e. 55 minutes over 108 days). Among those, a total of 73 potential avalanches were identified, most of them occurring during three independently documented avalanche episodes. These findings demonstrate that DAS represents a viable and cost-effective solution for operational real-time avalanche monitoring, with potential applicability to broader natural hazard detection.
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Status: final response (author comments only)
- RC1: 'Comment on egusphere-2026-2373', Antoine Turquet, 16 Jul 2026
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RC2: 'Comment on egusphere-2026-2373', Anonymous Referee #2, 31 Aug 2026
Major comments:
247-252: This appears to be the main summary for the method's performance. There does not seem to be a specific section for avalanche detection statistics, even if using only confirmed avalanche events (line 289). I would expect the authors to report how many confirmed avalanches were detected and missed, together with event-level precision and recall where the available observations allow. If the independent catalog is insufficient for these calculations, this limitation and the resulting inability to estimate false negatives should be stated.
251: A quantitative comparison with conventional STA/LTA is also needed. Saying that it would 'likely' trigger quasi-continuously is insufficient.
Lines 323-328: The wording appears to signal that the 73 potential avalanches identified occupy the entire 4.5 per mille (open road) and 0.36 per mille (closed road) of detections. There should be more clarity, not only in this section, but also before in the manuscrupt regarding what these numbers actually represent. For example, explicitly mentioning that the possible avalanches were manually picked from the trigger report.
Line 335-336: Applicability to other hazards is not established. Lahars and debris flows can produce coherent activity along channels, potentially resembling the traffic signature that this method rejects, so transfer would require hazard-specific and site-specific calibration and validation.
Minor comments:
Line 21: “several hundred million Swiss francs”
Line 30: Review also https://doi.org/10.1029/2020JF005741 and https://doi.org/10.1002/2014GL061254 for applications in other geographic contexts.
Line 44: See https://doi.org/10.1016/j.jvolgeores.2018.09.007 and https://arc.lib.montana.edu/snow-science/objects/ISSW2024_O8.2.pdf
Lines 45, 50: remove the space in “Pérez- Guillén”
Line 46: “Detections at distances of up to 15 km from an avalanche”
Line 71 and Fig. 9 caption: replace “noises” with “noise” or “noise sources”
Line 80: “tap tests on site”
Lines 90, 93: “As an additional assessment tool” and “Finally, observations…”
Fig. 1 caption: “Map data”
Fig. “Signals at distances <1 km are mostly generated by cars”
Fig. 5 caption: “in the early afternoon of 15 April”
Lines 128–135: standardize the notation as (f)–(k)
Lines 139–140: use “in real time” and remove the comma in “interpretability, and reproducibility”
Line 153: “channel by channel”
Line 166: “snow avalanches” (no hyphen)
Line 198: the apostrophe after filter, at the end right after the colon:
Line 205: “small avalanches”
Fig. 8 caption: “each individual car”
Fig. 9 caption: “an NVR patch”
Line 222: “referred to as”
Fig. 11 caption: “ “Burst events” instead of "Bursts" (singular) and “right hand side panel” should be “right-hand panel”.
Line 246: “closely spaced”.
Line 262: “vehicle-related” (with hyphen)
Line 264: “truck-generated” (with hyphen)
Line 280: “on the night of”
Line 288: insert a comma after the parenthesis ending “raw strain-rate data)”
Line 313: “system’s sensitivity”.
Lines 324–325: weird wording: revise as “while near-field signals generated by cars very rarely triggered the detector”.
Line 334: “decision-making”
Line 339: “MATLAB”
121: Maybe this is discussed later, but could this inform any potential for avalanches whose path do not intercept the FO?
128: This paragraph is formatted as an image caption. Ideally, it can be rewritten in prose without explicit panel mentions. Instead, something like "this avalanche does not include clear modes in its time-space domain as shown in Fig. 5c". See: https://publications.copernicus.org/for_authors/manuscript_preparation.html
119-123 and Fig. 3: Explain how the exact 19 March event time was independently constrained when the deposit was photographed on 25 March (was this aided by the DAS results?). Fig. 3 should include the data of the actual photo collection.
Citation: https://doi.org/10.5194/egusphere-2026-2373-RC2
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Dear Editors and Authors,
I have read the manuscript, 'Method for near real-time detection of snow avalanches using Distributed Acoustic Sensing.' The study is very interesting and presents valuable findings, and the manuscript itself is clear and well-organized. The work represents a strong contribution to DAS-based avalanche monitoring, particularly because it addresses the important operational challenge of distinguishing avalanche signals from anthropogenic noise.
I have only a few comments and suggestions that may help clarify the methodological scope and communicate the results more effectively.
General comments
1) The proposed detector seems to work well with avalanches that exhibit weak or delayed low-frequency STA/LTA responses relative to their full-band responses. However, large avalanches or the avalanches that are very close to the cable may generate higher/faster low-frequency STA/LTA responses and thus lower HVR amplitudes. Such events could therefore be missed or potentially misclassified as moving anthropogenic sources. It would be useful for the authors to discuss this potential limitation and clarify whether events with strong simultaneous low- and high-frequency responses were observed in the dataset.
2) The (1/\sqrt{2}) term in Equation 2 is not sufficiently explained. In its current form, assuming both STA/LTA quantities fluctuate around one during stationary background noise, the resulting attribute does not appear to fluctuate around zero.
3) A discussion of false negatives would be valuable for understanding the limitations and operational applicability of the method. Were there independently observed avalanches that the system failed to detect?
4) It would be a nice add-on if the authors could discuss the seismo-acoustic pathways of avalanche signals, signal phases and limitations of DAS more explicitly.