There is an ongoing need for a long-term Grizzly Bear Management Plan in Yoho National Park as a result of human-bear conflicts and periodic human mortality. Avalanche slopes offer preferred feeding sites to the grizzly bear population, and hence a more detailed knowledge of their location and extent is needed as a management tool. Landsat Thematic Mapper (TM) satellite image bands, a normalized difference vegetation index (NDVI), and the principal component associated with "greenness" (derived from the TM image data), along with digital elevation model variables provided the best classification with an avalanche slope accuracy of 82%. The classified data were imported into a geographic information system (GIS) and the area of the avalanche slopes determined to be 66 km2 or approximately 5% of the total park area. The resulting GIS database is being used by the park for management purposes.