Minnesota area affected by July 4, 1999 blowdown

Forest Disturbance Mapping

On July 4, 1999, a severe windstorm blew down over 30 million trees across nearly 500,000 acres within the Boundary Water Canoe and Wilderness Area in northeastern Minnesota.  The storm disturbance covered three Minnesota counties and the southern portion of Ontario, Canada.

Within and surrounding this area, there is a gradient of disturbance severity from no damage to complete canopy and understory tree mortality.  Due to the unprecedented severity of the storm, there was a need to accurately and quickly determine the extent, severity, and spatial pattern of the disturbance for the purposes of initial response, forest management, and research planning.

Our objective in this study has been to assess the potential use of high-resolution satellite imagery to map forest windstorm disturbance and produce a map that includes both accurate damage delineation, as well as consistent severity classes.

Since the IKONOS satellite was launched in September 1999, commercial high-resolution satellite imagery was not available for dates prior to this storm. Similarly, future forest storm sites will rarely have acquired high-resolution satellite imagery of a ‘before’ date. Therefore, our goal is to design a simple methodology that uses single date imagery to map disturbance extent and severity using 18 scenes of IKONOS imagery acquired between May 19 and August 23, 2000.

Please visit the Northeastern Minnesota Storm Research Information project website to learn more about this project.