3.1 Introduction

Snowpack evolution is often referred to as snowpack metamorphism. The characteristics of a snowpack, such as its depth, density, layering, degree of bonding, and temperature, change over time regardless of whether more precipitation falls. Metamorphic processes become more important as dry periods persist.

Our study of snowpack evolution spans three sections.

  • In this first section, we examine the basic processes that affect snowpack evolution, such as conduction and radiation
  • In the next two sections (Scenarios 1 and 2), we use scenarios to explore other factors that affect snowpack evolution, such as the different types of weather events; both scenarios occur over the same period of time (from fall to spring) but take place in different types of terrain (a relatively flat, open area vs. a mountainous region)

Before getting started, we need to define some terms.

Snow grains refer to the ice crystals within a snowpack rather than those in the atmosphere.

Bonding refers to the degree to which grains are aggregated (clustered together) or not. For new snowfall, the degree of bonding is generally greater if the crystals are of similar sizes.

Ethan Greene on bonding: