PREDICTING LANDSLIDE HAZARDS IN THE GREATER DULUTH AREA NORTH TO THE KNIFE RIVER ALONG THE NORTH SHORE OF LAKE SUPERIOR

Streams along the western end of the North Shore of Lake Superior contain hazardous slopes that have produced dangerous landslides both historically and in recent time but unfortunately, no known landslide hazard maps have been created for these specific locations. Eroding thick layers of glacial till deposited on top of bedrock in high relief areas located near stream banks contain the perfect geologic setting needed for slope failure to occur. We are mapping landslide hazard potential as steep high relief areas along streams with little to no bedrock exposure topped with thick glacial till. To further investigate this, we are developing predictor variables using lidar topography to map in areas of high relief, Minnesota Geological Survey (MGS) maps showing bedrock exposure, and Natural Resources Conservation Service (NRCS) soils maps and MGS maps that indicate depth to bedrock. These predictor variables are being mapped in the area between Duluth and Knife River and compared with observations of slope failures collected after a major 500-year flood event on June 19-20, 2012, by a series of volunteer observers and U of MN-Duluth graduate students.