Figures 7.2 and 7.3 compare the results of FASST with those of SNTHERM against the
measured values for two sites in Colorado. SNTHERM (Jordan 1991a) is considered the
most physically based snow model. The Buffalo Pass site is characterized by an
accumulation period followed by an ablation period that begins on approximately day
130. Both models accurately transition between the two seasons. FASST underestimates
the meltout date by three days while SNTHERM overestimates it by three days. Within
five days is considered accurate (Holcombe et al. 2004). The absolute (average of model
measured) and relative (average of [modelmeasured]/measured) errors for both models
are 8% and 3%, respectively.
The snowpack at the Illinois River site, Figure 7.3, is characterized as thin, ephemeral,
and windblown. This is a more difficult modeling scenario. Despite this, both models do
well. The absolute error is < 1% while the relative error is 2 % for SNTHERM and 11%
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