Crime Scene Investigator Network Newsletter

Introduction
Snow impressions have presented a myriad of challenges to criminalists for decades. Snow impressions are usually only encountered seasonally or at high elevations. Therefore, investigators do not have many opportunities to develop or hone their snow-casting expertise. As a result, casting in snow has, in many ways, become a lost art. Modern criminalists are losing their capacity to recognize the characteristics of snow and how those characteristics dictate the choice of appropriate casting methods. Many examiners and instructors have become too dependent on the exclusive use of aerosol wax products and dental stone to cast snow impressions. As a result, alternative methods that may provide better results have been essentially abandoned. Because snow impressions are more susceptible to short-term change than impressions in soil or other materials because of local environmental conditions (temperature, solar exposure, precipitation, and wind), understanding snow morphology and the effects of environmental influences on impression conditions may assist the investigator in choosing an appropriate technique for casting under site-specific conditions.

This paper will explore the art of snow impression casting in terms of the varying properties that can occur in snowpacks. Linking the complexities of a snowpack near a crime scene with the various casting techniques available may provide for a more informed decision of what technique(s) might best render a high-quality cast. To this end, this paper will provide a detailed discussion of snowpack characteristics and morphology that the investigator may consider. This discussion will be followed by a description of casting techniques that can be employed under different snowpack conditions. Closing remarks and conclusions will then be presented.

Snowpack Properties
In the literature, several property classifications have been noted that are pertinent to snowpack evaluation. Metamorphic and bulk properties provide the investigator with information on the evolution of a snowpack with time. Mechanical properties are important in understanding the deformation of a snowpack for casting purposes. Frictional properties often associated with

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