Amodified version of the Colorado Rockfall Hazard Rating System (RHRS) was created by adding several geological and climatic factors that have been recently shown to contribute to rockfall. The modified RHRS was then used on slopes distributed throughout the western, mountainous terrain in Colorado, including sites where only cut slopes were rated and siteswhere both the cut portion and the higher, uncut portionwere both judged to contribute to the rockfall hazard. In total, 355 slopes were rated: for crystalline rocks, 147 cut slopes and 77 total slopes, for sedimentary rocks, 43 cut slopes and 31 total slopes, and for block-in-matrix materials, 45 cut slopes and 12 total slopes. Univariate least squares regressionwas used to find parameters  that had a statistically significant influence on the total hazard score. This subset was then analyzed using ordinal logistic regression to rank these parameters against one another to determine which had the most significant influence on the total hazard score. Finally, statistically significant parameters from these regressions were analyzed using stepwise regression to obtain predictive equations to estimate the total hazard score for each of the slope types analyzed based on the scores of a few parameters.