Engineer outlines steep‑slope hazards and code options for Pitkin County

Dr. Andrew Earls of Brightwater Engineers walked Pitkin County through how slope is measured and why steep terrain increases hazard, saying local codes typically regulate slopes “in excess of about 30%.” He described the engineering concept of factor of safety and global stability analysis as tools counties can require to determine whether proposed development increases slide risk. “When you get above 45%, you have very steep slopes and youre getting very close to what we call the angle of repose,” Earls said, underscoring the sensitivity of slopes near that threshold.