The safety of people in a winter, backcountry mountain environment is presented in terms of margins of security and margins of survival. The elements of a security deter- mination are expanded on assessments of snow stability, hazard, andrisk. Processesof reasoningby mountainguides in light of many uncer tainties ar e outlined.
Risk management is treatedin terms of human psychology.
The profession of guiding is both an art and a science. The challenge,for practicing guides, is to merge elements of art and of science in their work. This paper presents a conceptual framework for safety determinations by guides on behalf of clients. Mountain guides consider safety in a situational context. Let us call this cognitive sequence the security determination.