Avalanche awareness and safety for snow scientists in the field

During the winter of 1970-71, avalanches in the United States caught 58 people, buried 46, and killed 12. Snow scientists should periodically update their knowledge of how to classify avalanche events and to evaluate avalanche hazards. A practical, three-part classification of avalanches is proposed. Part I includes static observations made following the event; Part II includes dynamic observations made at the time of the event; and Part III includes genetic deductions based on a description of the meteorological background,. Evaluation of hazard is possible through careful observation of the definitive factors which cause avalanches; accumulation of new-fallen and wind-transported snow, free water percolation through the snowpack, and progressive weakening of internal layers of the snowpack. Knowledge of avalanche classification and hazard evaluation together with the use of sound judgement, should promote avalanche awareness and safety.