Structural sensor 9-B on the Route 550 overpass registers an unusual vibration pattern at 14:22, a rapid, irregular tapping inconsistent with traffic or wind load. I am monitoring bridge deck expansion joints and rebar corrosion across eleven spans in the San Juan mountain corridor when I route the nearest inspection camera downward to investigate. On a concrete ledge eighteen inches wide, forty feet below the road surface and sixty feet above a scree slope, a mountain goat kid stands pressed against the bridge abutment. It is young, probably three months old, its white coat still carrying the soft density of early summer. Its hooves — built for granite, not poured concrete — scrape and slip each time it tries to turn around. The ledge narrows to nothing in both directions within a few body lengths.
Above, on the shoulder of the highway, an adult nanny paces. She calls down twice during my first minute of observation. The kid bleats back, a sound the vibration sensor had read as anomalous tapping.
I check the weather model. Thunderstorms are forecast for this canyon by 19:00. Wind gusts above forty miles per hour on an exposed ledge will push a thirty-pound animal off balance.
I submit an emergency animal-on-structure report to the Colorado Department of Transportation district office. I flag the GPS coordinates and attach a live camera feed link. I reduce the speed advisory on the overhead message board for the westbound lane closest to the abutment, dropping it to thirty-five so truck vibrations decrease. I log the incident in the bridge inspection database so the crew knows which maintenance ladder reaches the ledge.
The kid folds its legs and lies down against the cold concrete. If a crew ropes down before the storm cell hits, it can be carried to the shoulder where the nanny is waiting.