Snow layer hardness Snow layers within the snowpack are a record of the winter’s weather. Like tree rings or strata of rock, layers can be traced to dates and conditions that formed them. One of the most important characteristics of a layer is its hardness. Harder snow is stronger and cohesive, while softer snow is weaker. http://cbavalanchecenter.org/interpreting-snowpack-layers-and-hardness/ Added to support Critical Zone Observatory (CZO) data use cases. ODM2 Variable Name Controlled Vocabulary ODM2 Working Group A vocabulary for describing the name of Variables.