ET from Snow

ET from snow is a sum of the ET from wet snow and dry snow storages.

(20.1)   

First, ET will be removed from the wet snow storage, if it exists,

where ET_ref is the Reference Evapotranspiration (V1 p. 234) before being reduce by the Crop Coefficient, k_c, that is specified in the Vegetation Develop­ment Table (V1 p. 405).

However, if there is insufficient wet snow storage, then ET will also be removed from dry snow as sublimation using

(20.2)   

where S_f is the sublimation reduction factor found on the Snow Melt (V1 p. 239), which reduces the amount of ET that can be removed from dry snow due to the extra energy required to sublimate snow.

If there is not enough snow storage then ET_snow will reduce the snow storage to zero.