Snowpack water equivalent

One of the most common properties of snowpacks needed by snow hydrologists is snowpack water equivalent. The water equivalent of a snowpack represents the liquid water that would be released upon complete melting of the snowpack.Water equivalent is measured directly or computed from measurements of depth and density of the snowpack as:

 

 

Given measurements of snowpack depth of 0.22 m and snowpack density of 256 kg m−3, the snowpack water equivalent would be:

 

   

Snowpack water equivalent includes any liquid water that may be stored in the snowpack along with the ice crystals at the time of measurement. Snowpack water equivalent is treated as a primary input to the discussion

of snow hydrology.

 

SWE can be indirectly determined trough snow density and depth. On field measurements do not measure SWE by itself, we measure snow depth and density (weight at the end) with a very rustic (?) and simple system.
   

Figure: Snow depth measurement. Farellones, Chile. ( 33.36S, 70,31W)

 

We first measure snow depth with a regular ruler, and then at a certain given snow depth we introduce a wedge. Carefully you slide a cutter at the top of the wedge and you will have a piece of snow inside this wedge (imagine it as a piece of pizza).

    

Figure: 'Wedge' inside the snowpack. Farellones, Chile

 

Figure: Snow perfectly cut and fit into the 'wedge' . Farellones, Chile.

 

Since the 'wedge' mass is known, weighting it you will have snow mass. Wedge volume it is also known (250cc or 1000cc), thus you can determine snow density at that given depth. Then with the snowdepth you can estimate Snow Water Equivalent.