Speaker
Dr
Hannah Vickers
(Northern Research Insitute)
Description
Snow avalanches, both natural and human released, occur frequently throughout the winter season in the mountainous regions of Troms county in northern Norway. These avalanches can lead to road closures, community evacuations and fatalities. It is therefore desirable to develop a method by which snow avalanches can be actively mapped and monitored, especially in avalanche-prone areas that are not easily accessible for observation by human means. Avalanche debris can be observed over large spatial areas, independent of local weather and light conditions by synthetic aperture radar (SAR) satellites that can measure snow remotely. The recently launched Sentinel-1A satellite makes it possible to acquire SAR images within the entire county of Troms with updates as often as every 2-4 days. We have acquired and built up a database of Sentinel-1A images since the satellite became operational in September 2014. This database has allowed us to identify and monitor several key areas in Troms county where avalanches release frequently during the entire winter season. We have exploited the Sentinel-1A data to firstly show that Sentinel-1A images can be used to observe avalanche debris and secondly to develop an automated avalanche debris detection algorithm which makes use of change detection and object classification methods. In this work we give an overview of the method and present results of the automatic detection algorithm where we have applied it to selected areas in Troms county where repeated avalanche activity was observed throughout the winter season, including both wet and dry avalanche types. We evaluate the accuracy of the method by means of gathering incident reports, in-situ field measurements and high resolution SAR (RS-2 ultrafine) images. We show that the method delivers results that agree well with the supporting observations and could play an effective role in mapping avalanche-prone zones and routine monitoring of these areas within Troms county as well as other avalanche-prone regions that are observable by SAR. We also report on the outstanding challenges that must be overcome to fine-tune the current detection algorithm.
Primary author
Dr
Hannah Vickers
(Northern Research Insitute)
Co-authors
Dr
Eirik Malnes
(Norut)
Dr
Heidi Hindberg
(Norut)
Dr
Markus Eckerstorfer
(Norut)
