Received: 28 Jan 2015 – Accepted for review: 06 Mar 2015 – Discussion started: 24 Mar 2015
Abstract. Snow avalanches are natural hazards, occurring in snow covered mountain terrain worldwide. Present avalanche research and forecasting relies on complete avalanche activity records in a given area over an entire winter season, which cannot be provided with traditional, mainly field based methods. Remote sensing, using weather, and light independent SAR satellites has the potential of filling these data gaps, however, to date their use was limited by high acquisition costs, long repeat cycles, and small ground swath. Sentinel-1A (S1A), on the other hand, operational since October 2014 provides free-of-charge, 20 m spatial resolution, 250 km × 150 km ground swath images every 12 days. In this paper, we present for the first time, that it is possible to detect avalanche debris using S1A images. We successfully apply a change detection method that enhances avalanche debris zones, by comparing repeat pass images before and after the avalanche occurred. Due to the increase in backscatter from avalanche debris, manual detection is possible. With this first proof-of-concept, we show the detection of 489 avalanche debris zones in a S1A image from 6 January 2015, covering the counties Troms and parts of Nordland in Northern Norway. We validate our avalanche detection using very high resolution Radarsat-2 Ultrafine images, as well as extensive field reconnaissance. Our results give us confidence, that S1A detection of avalanches is a critical step towards operational use of SAR avalanche detection in avalanche forecasting.
How to cite: Malnes, E., Eckerstorfer, M., and Vickers, H.: First Sentinel-1 detections of avalanche debris, The Cryosphere Discuss., 9, 1943–1963, https://doi.org/10.5194/tcd-9-1943-2015, 2015.
During an avalanche cycle in January 2015 in northern Norway we used repeat pass Sentinel-1 images to map avalanches. Avalanche debris shows up as increased backscatter in repeat pass images. We detected 489 avalanches in a single scene. Results were validated using high resolution SAR data and field reconnaissance. The results are very promising, and pave the way for operational avalanche monitoring using SAR. Sentinel-1 grant frequent coverage with high quality to monitor avalanches.
During an avalanche cycle in January 2015 in northern Norway we used repeat pass Sentinel-1...