A surgical mask is used inside the operating room or during other sterile procedure areas to protect the patient environment from contamination. Surgical masks have ties so that they can be adjusted for fit, and are tied over the top of a surgical or bouffant cap.
rockfall. 1  an act or instance of the falling of rock, as in a cave-in or an avalanche. 2  a mass of rocks that have fallen: to be trapped under a rockfall.
Field studies have also shown that freezing and melting of ice within cracks may control rockfall timing in some areas, although the falls generally seem to be more closely related to melting rather than ice wedging.