  We examine the light curve of the July-August 2001 superoutburst of WZ
Sagittae. During the decline from maximum light the locally defined decay time
increases from ~4 d/mag to ~12 d/mag over the first ~15 d of the ~25 d
superoutburst, as the system faded from m_V~8.5 to m_V~10. The superoutburst is
caused by the sudden accretion of ~10^{24} g of gas onto the white dwarf, and
the deviation from exponentiality in the decay light curve is expected
qualitatively during a ``viscous decay'' in which the dominant mode of
depletion of the gas stored in the accretion disk is accretion onto the central
object. In other words, as the mass of the accretion disk decreases, the
viscous time scale increases. We show that the data are also quantitatively
consistent with the theoretical viscous decay time, both calculated via a
simple scaling and also from time dependent calculations, when one adopts
standard model parameters for WZ Sge.
