Snow-Cover Properties and Processes
During the last 20 years, considerable progress has been made in our understanding of the prop-
erties of seasonal snow covers and the physical processes controlling changes to these properties.
An improved understanding of these provides the basis required for a better understanding and
ability to predict the complex role snow plays in northern environments. These include, for
example, streamflow, climate, fluxes of nutrients through the snowpack, and subnivean ecology.
An improved predictive ability also provides the ability to better alleviate a variety of environ-
mental issues, including the rapid release of pollutants from snow-covered landscapes, as well as
a variety of climate-change-related issues.
This paper will outline recent progress made in understanding the following properties and pro-
cesses, and attempt to provide a synthesis of the current state of our understanding and critical
areas for future research. Issues to be considered include regional variations in snow-cover
properties, and processes controlling grain size, layering, ice layers, surface energy fluxes, blow-
ing snow, forest canopy interception, energy fluxes within the snow cover, meltwater flux
through the snow cover, runoff, and frozen soil infiltration, for example.
One of the major features of recent research into these snow properties and processes is the ongo-
ing recognition of the importance of the heterogeneous nature of the snow cover at all scales, and
attempts to properly consider this spatial variability. Although earlier work recognized the great
spatial variability of snow cover, limited theoretical understanding and/or computational power
resulted in most studies considering the snow cover as being spatially homogeneous. With
increasing theoretical understanding and computational power, researchers have increasingly
attempted to incorporate spatial variability. This has included, for example, the role of patchy
snow cover in controlling surface energy fluxes, flow fingering during vertical water percolation,
the fractal nature of snow patches, and the layered nature of snowpacks. A major focus of this
paper will be on reviewing our progress to date on such factors.
NHRI, National Hydrology Research Centre, 11 Innovation Boulevard, Saskatoon S7N 3H5, Canada