Unusually strong winter storms in 2006 and 2007 generated substantial precipitation and high winds across Vancouver Island, causing increased landslide and blowdown events. Working with the Ministry of Environment, Caslys performed multi-temporal mapping to understand the extent and increase in damage compared to previous seasons.
Change detection analyses, using multi-spectral SPOT imagery, was conducted to facilitate the comparison between two prior winter seasons. The analyses identified new landslides and blowdown areas for each time period, as well as forest harvest cut blocks and recent road construction that were intended for other research programs. Disturbed areas were mapped and their spatial characteristics quantified to summarize the magnitude of disturbance and provide spatial data products to decision makers.
The change detection analysis clearly delineated disturbance regions with a high level of detail, allowing for the detection and quantification of landslide and blowdown events caused by the 2006/2007 storms. The delineated cutblock polygons were used in subsequent analysis by the Ministry of Environment to evaluate lost marbled murrelet habitat and other important wildlife areas.