Measured precipitation
The heat storage of the snow cover is represented in the model by the heat deficit.
The heat deficit indicates the amount of heat that must be added to return the snow cover to an isothermal state of 0oC with the same liquid-water content as when the heat deficit was previously zero.
After the heat deficit returns to zero, surface melt water or rainwater can again contribute to liquid-water storage or snow cover outflow.
Physically, the heat deficit consists of liquid-water that is frozen within the snow cover when heat is lost and snow that is at temperatures below 0oC.
The physical form of the heat deficit is not important; only the total deficit needs to be known.
The model keeps a continuous accounting (on a 6-hour basis) of the total heat deficit.
