The snowmelt model in GAWSER (Guelph All-Weather Sequential-Events Runoff Model) (Schroeter & Associates, 1996) was used to model the snow pack water balance. Six processes (refreeze, compaction, new snow deposition, rain deposition, snowmelt and release of liquid water water) are considered in the model as show in the figure below.


It’s assumed that the snow pack is consist of two parts: solid water content (SWC) and liquid water content (LWC). Snow pack is first formed with new snow adding to solid water content. With varying temperature, snow may be melted and added to liquid water content. The liquid water in liquid water content may also be compacted and added back to solid water content. When the amount of liquid water exceeds the holding capacity of the snow pack, it’s then released to generate runoff.