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slopes. All material on hillslopes is influenced by downslope gravita- tional stress. Direct evidence that soil creep is active includes disrupted vegetation and soil ripples (Rogers and Soule, 1976). Soil creep is fre- quently found in association with landslides, debris-avalanches and debris- slides which are discussed below. Consequently, areas of soil creep may serve to indicate more serious hazards or sites where such hazards could be aggravated by man's activities. Landslides. Landslide.s and areas susceptible to landsliding are most commonly located on north-facing, moderate to steep slopes where colluvium thickness is 1 to 2 m or greater. Colluvium derived from metamorphic rock appears to bemore susceptible to landsliding than that composed of granitic grus. Both severity and extent of landslide hazard appear to increase as slope or thickness of colluvium increase. Predominantly north-facing slopes tend to be associated with hazard because they retain moisture longer in winter and can support a relatively dense coniferous forest. The binding together of the regolith by tree roots promotes the relatively thick ac- cumulation of colluvium. Most of the classical evidence for landsliding discussed by Sharpe (1938) and Varnes (1958) is applicable to the Big Thomp- son Canyon. Of special note, however, is the widespread occurrence of land- slides caused by the undercutting of slopes by the Big Thompson River and its tributaries during the recent flooding. Rockfalls and rockslides. As it is apparent to even the most casual visitor to the Big Thompson Canyon, rockfalls and rockslides are nearly ubiquitous on very steep slopes. Scree deposits, other rockfall debris, jointed bedrock cliffs, and loose, fresh cobble to large boulder size material on hills lopes are all indicative of rockfall and rockslide hazard areas. Although general identification of rockfall and rockslide hazard 28 I I I I I I I I I I I I I I I I I I