THE PHYSICS OF AVALANCHES
Matthew Whitman
University of Alaska Fairbanks
Physics 211 Project, Fall 2002

    Avalanches kill backcountry recreationalists every year, including skiers, snowboarders, snowshoers, and snowmachiners. All backcountry users should have knowledge of the basic physics of avalanches to help them evaluate local and regional potential for slides. The foundation of this knowledge comes from understanding how the surrounding environmental conditions in previous weeks, previous days, and the day in question all contribute to snow stability or instability, and how specific factors affect snow on a micro-scale, which determines how snow slopes will behave on a macro-scale.  There are two major types of avalanches (excluding debris avalanches from broken cornices and ice formations).  These are point releases, or loose snow slides, and slab avalanches.  While point releases can be dangerous and should be avoided, slab avalanches are much more catastrophic and account for most of the backcountry avalanche disasters involving humans.  Basic physics of point releases are discussed here, followed by a discussion on the basic physics of slab avalanches, and how external factors contribute to the stability or instability of a snow covered slope.





Material presented is only an overview of the basic fundamentals of avalanche physics.  Individuals interested in backcountry travel should examine sources in the bibliography more closely and learn skills from experts.